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At least 19 recordsLinked to original sources
PubMed1990

Generation of a different type of beta-kallikrein from porcine pancreatic alpha-kallikrein by the action of chymotrypsin--observation of proteolytic processing occurring around "kallikrein autolysis loop" region.

The generation of a different type of beta-kallikrein, designated C beta-kallikrein, from alpha-kallikrein by chymotryptic action was ascertained by the following observations: 1) When alpha-kallikrein was incubated with chymotrypsin, an increase of esterolytic activity of kallikrein was observed. 2) In sodium dodecyl sulfate polyacrylamide gel electrophoresis, C beta-kallikrein was found to be different from the beta-kallikrein obtained from alpha-kallikrein by tryptic digestion, and was designated T beta-kallikrein. 3) N-Terminal amino acid sequence analyses of internal light and heavy chains of C beta-kallikrein indicated that N-termini of the light and the heavy chains were isoleucine and lysine, respectively, and that the heavy chain had most of the "kallikrein autolysis loop" sequence in its N-terminal end. In the case of T beta-kallikrein, N-termini of the light and the heavy chains were isoleucine and alanine, respectively, and the light chain retained the "kallikrein autolysis loop" region in its C-terminal end. These observations demonstrated that C beta-kallikrein was different from the beta-kallikrein prepared from autolyzed pancreas, A beta-kallikrein, which had lost the "kallikrein autolysis loop" sequence. Structural differences of the above four kallikreins (alpha-, T beta-, C beta-, and A beta-) result in somewhat different enzyme properties. The kinetic constants for the hydrolysis of synthetic substrates (N alpha-benzoyl-L-arginine ethyl ester and N alpha-tosyl-L-arginine methyl ester) of these kallikreins differed from each other, and inhibitory profiles against alpha 1-antitrypsin were also different.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1983

Increases in plasma kallikrein-like and pancreas kallikrein-like substances after administration of pancreas or plasma kallikrein.

Differences between the concentration of a kallikrein-like substance in blood obtained by the peptide-MCA method and that obtained by the TAME (N-tosyl-l-arginine methyl ester) method by administering pancreas kallikrein to rabbits have been recognized already and the existence of a Substance X was evaluated. In the present study, it was revealed that administration of pancreas kallikrein resulted in inactivation of kallikrein in the substrate in gut homogenates and homogenates of various organs except for the pancreas. In the pancreas homogenate, inactivation was not observed. On the other hand, there was a possibility that at least part of Substance X existed due to plasma kallikrein. Thus, the concentration of plasma kallikrein in plasma after administration of pancreas kallikrein was determined. A pattern similar to the concentration curve of Substance X was obtained. Thus, it was clarified that plasma kallikrein-like substance, at least, increased when pancreas kallikrein was administered. On the contrary, when plasma kallikrein was administered to the rabbit duodenum, the concentration of pancreas kallikrein-like substance in plasma increased. It was also clarified that plasma kallikrein-like substance increased in vitro by adding pancreas kallikrein to the blood or plasma, whereas the in vitro addition of plasma kallikrein to the blood induced its decomposition and a slight increase in pancreas kallikrein-like substance, and the addition of plasma kallikrein to the plasma induced an increase in plasma kallikrein and a slight increase in pancreas kallikrein-like substance.

Animals↗
PubMed1992

Protein products of the rat kallikrein gene family. Substrate specificities of kallikrein rK2 (tonin) and kallikrein rK9.

Two closely related kallikrein-like proteinases having little activity toward the standard synthetic amide substrates of tissue kallikreins were isolated from the rat submandibular gland. They were found to be the protein products of the rKlk2 (tonin) and the rKlk9 genes by amino acid sequence analysis (nomenclature of the genes and proteins of the kallikrein family is according to the proposal of the discussion panel from the participants of the KININ '91 meeting held Sept. 8-14, 1991, in Munich, Germany). These two proteinases of similar structure also had very similar physicochemical properties. They differed from other kallikrein-related proteinases in having high pHi values of 6.20 (rK2) and 6.85 (rK9). Kallikrein rK2 was purified as a single peptide chain, whereas rK9 appeared as a two-chain protein after reduction. Their enzymatic properties were also very similar and differed significantly from those of other rat kallikrein-related proteinases. Unlike the five other kallikrein-related proteinases we have purified so far, kallikrein rK9 was not inhibited by aprotinin. rK9 also differed from rK2 by its tissue localization. The prostate gland contained only rK9 where it was the major kallikrein-like component. The amino acids preferentially accommodated by the proteinase S3 to S2' subsites were identified using synthetic amide and protein substrates. Unlike other kallikrein-related proteinases, rK2 had a prevalent chymotrypsin-like specificity, whereas rK9 had both chymotrypsin-like and trypsin-like properties. Both rK2 and rK9 preferred a prolyl residue in position P2 of the substrate and did not accommodate bulky and hydrophobic residues at that position, as did most of the other kallikrein-related proteinases. This P2-proline-directed specificity is necessary for processing the precursors of several biologically active peptides. Subsites accommodating residues COOH-terminal to the scissile bond were also important in determining the overall substrate specificity of these proteinases. rK2 and rK9 both showed a preference for hydrophobic residues in P2'. Other subsites upstream of the S3 subsite were found to intervene in substrate binding and hydrolysis. The restricted specificity of rK2 and rK9 is consistent with the presence of an extended substrate binding site, and hence with a processing enzyme function. Their P1 specificities enabled both proteinases to release angiotensin II from angiotensinogen and from angiotensinogen I, but rK9 was at least 100 times less active than rK2 on both substrates. The substrate specificities of rK2 and rK9 were correlated with key amino acids defining their substrate binding site.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1993

High molecular weight kininogen potentiates the heparin-accelerated inhibition of plasma kallikrein by antithrombin: role for antithrombin in the regulation of kallikrein.

The effects of previously characterized interactions of high molecular weight kininogen (H-kininogen) with plasma kallikrein and with heparin on the regulation of kallikrein by the heparin-activated inhibitor, antithrombin, were investigated. H-kininogen, at levels sufficient to fully complex kallikrein, greatly potentiated the acceleration of antithrombin inhibition of kallikrein produced by heparin with high affinity for antithrombin. At I = 0.15, pH 7.4, 25 degrees C, kininogen thus maximally increased the heparin enhancement of the second-order rate constant for the antithrombin-kallikrein reaction from 13-fold (1.6 x 10(2) M-1 s-1 to 2.1 x 10(3) M-1 s-1) to 1200-fold (1.9 x 10(5) M-1 s-1). In contrast, H-kininogen had no effect on the antithrombin-kallikrein reaction in the absence of heparin, nor did the protein enhance the rate constants of 1.7 x 10(4) and 3.4 x 10(4) M-1 s-1 for kallikrein reactions with its primary plasma inhibitors C1-inhibitor and alpha 2-macroglobulin, respectively, in the absence or presence of heparin. Consistent with these results, SDS gel electrophoresis of the 125I-labeled kallikrein-inhibitor complexes formed in a mixture of these kallikrein inhibitors at their relative plasma concentrations indicated that antithrombin effectively competed with C1-inhibitor and alpha 2-macroglobulin for kallikrein, accounting for 54% of the total kallikrein complexes, only when both heparin and H-kininogen were present. Similarly, the presence of therapeutic levels of heparin (approximately 1 unit/mL) in normal, factor XII-deficient, and prekallikrein-deficient plasmas enhanced the rate of inactivation of added kallikrein by 2.3-fold and significantly altered the partitioning of radiolabeled kallikrein from predominantly C1-inhibitor and alpha 2-macroglobulin complexes (86-92%) to mostly antithrombin complexes (50-53%). Experiments in antithrombin-deficient and H-kininogen-deficient plasmas confirmed that the enhanced kallikrein inactivation rate and predominant formation of antithrombin-kallikrein complexes in heparinized plasma were dependent on antithrombin and H-kininogen. The contribution of antithrombin to kallikrein inhibition in plasma remained significant (approximately 40-70%) at optimal concentrations of unfractionated or size- and antithrombin affinity-fractionated heparin, in the presence of plasma levels of calcium and zinc ions, at 37 degrees C, and with minimal plasma dilution. These results suggest that antithrombin and H-kininogen may play important roles in the regulation of kallikrein activity in the presence of heparin or heparin-like glycosaminoglycans.

Antithrombins↗
PubMed1985

Protein-protein interactions in contact activation of blood coagulation. Binding of high molecular weight kininogen and the 5-(iodoacetamido) fluorescein-labeled kininogen light chain to prekallikrein, kallikrein, and the separated kallikrein heavy and light chains.

Binding of the 5-(iodoacetamido)fluorescein (IAF)-labeled high molecular weight (HMW) kininogen light chain to prekallikrein and D-Phe-Phe-Arg-CH2Cl-inactivated kallikrein was monitored by a 0.040 +/- 0.002 increase in fluorescence anisotropy. Indistinguishable average dissociation constants and stoichiometries of 14 +/- 3 nM and 1.1 +/- 0.1 mol of prekallikrein/mol of IAF-light chain and 17 +/- 3 nM and 0.9 +/- 0.1 mol of kallikrein/mol of IAF-light chain were determined for these interactions at pH 7.4, mu 0.14 and 22 degrees C. Prekallikrein which had been reduced and alkylated in 6 M guanidine HCl lost the ability to increase the fluorescence anisotropy of the IAF-kininogen light chain, suggesting that the native tertiary structure was required for tight binding. The kallikrein heavy and light chains were separated on the basis of the affinity of the heavy chain for HMW-kininogen-Sepharose, after mild reduction and alkylation of kallikrein under nondenaturing conditions. Under these conditions, alkylation with iodo [14C]acetamide demonstrated that only limited chemical modification had occurred. Binding of the IAF-kininogen light chain to the isolated alkylated kallikrein heavy chain, when compared to prekallikrein and kallikrein, was characterized by an indistinguishable increase in fluorescence anisotropy, average dissociation constant of 14 +/- 3 nM, and stoichiometry of 1.2 +/- 0.1 mol of kallikrein heavy chain/mol of IAF-light chain. In contrast, no binding of the D-Phe-Phe-Arg-CH2Cl-inactivated kallikrein light chain was detected at concentrations up to 500 nM. Furthermore, 300 nM kallikrein light chain did not affect IAF-kininogen light chain binding to prekallikrein, kallikrein, or the kallikrein heavy chain. The binding of monomeric single chain HMW-kininogen to prekallikrein, kallikrein, and the kallikrein heavy and light chains was studied using the IAF-kininogen light chain as a probe. Analysis of the competitive binding of HMW-kininogen gave average dissociation constants and stoichiometries of 12 +/- 2 nM and 1.2 +/- 0.1 mol of prekallikrein/mol of HMW-kininogen, 15 +/- 2 nM and 1.3 +/- 0.1 mol of kallikrein/mol of HMW-kininogen, 14 +/- 3 nM and 1.4 +/- 0.2 mol of kallikrein heavy chain/mol of HMW-kininogen, and no detectable effect of 300 nM kallikrein light chain on these interactions. We conclude that a specific, nonenzymatic interaction between sites located exclusively on the light chain of HMW-kininogen and the heavy chain of kallikrein or prekallikrein is responsible for the formation of 1:1 noncovalent complexes between these proteins.

Binding, Competitive↗
PubMed1990

Mitogenic effect of kallikrein from human urine on cultured human skin fibroblasts. Analysis of the combined action of kallikrein, insulin, and fibroblast growth factor on DNA and RNA synthesis.

Kallikrein isolated from human urine was capable of stimulating DNA and RNA synthesis in cultured human skin fibroblasts in media with a low serum content. The same concentration of kallikrein had a different effect on the DNA and RNA synthesis in different fibroblast lines, which was attributed to differences in the sensitivity of the cells to kallikrein. At a dose of 0.5 micrograms ml-1, kallikrein inactivated by heating at 100 degrees C caused an abrupt decrease in DNA synthesis in all the cell lines studied. When either active or inactivated kallikrein was added to the growth medium simultaneously with insulin there was a competitive effect on DNA and RNA synthesis. Preincubation of the cells with kallikrein prior to addition of insulin led to a reduction in the level of DNA synthesis compared to that seen upon simultaneous addition of kallikrein and insulin, suggesting that kallikrein and insulin competed for the same receptor. When kallikrein and fibroblast growth factor (FGF) were added simultaneously to the growth medium, there was a sharp decrease in both DNA and RNA synthesis in the cells compared to that seen on addition of FGF alone. Since heparin protected FGF from kallikrein inactivation, it is suggested that inactivation was caused by proteolytic degradation of part of the FGF molecule by kallikrein. It is concluded that kallikrein and insulin compete for the same receptor, possibly the insulin-like growth factor I (IGF-I), and that binding of kallikrein to this receptor is a prerequisite for mediation of the stimulatory effect of kallikrein on nucleic acid synthesis.

Cell Line↗
PubMed1992

Inhibition of tissue kallikrein by protein C inhibitor. Evidence for identity of protein C inhibitor with the kallikrein binding protein.

We studied the inhibition of tissue kallikrein by protein C inhibitor (PCI), a relatively unspecific heparin-dependent serine protease inhibitor present in plasma and urine. PCI inhibited the amidolytic activity (cleavage of H-D-valyl-L-leucyl-arginine-p-nitroaniline) of urinary kallikrein with an apparent second order rate constant of 2.3 x 10(4) M-1 s-1 and formed stable complexes (85 kDa) with urinary kallikrein as judged from silver-stained sodium dodecyl sulfate-polyacrylamide gels. Complex formation was time-dependent and was paralleled by a decrease in the intensity of the main PCI protein band (Mr = 57,000) and an increase in the intensity of the lower Mr (54,000) PCI form (cleaved inhibitor). Heparin interfered with the inhibition of tissue kallikrein by PCI and with the formation of tissue kallikrein-PCI complexes in a dose-dependent fashion and completely abolished PCI-tissue kallikrein interaction at 300 micrograms/ml. This is in contrast to findings on the interaction of PCI with all other target proteases studied so far (i.e. stimulation of inhibition by heparin) but is similar to the reaction pattern of 125I-labeled tissue kallikrein with so called kallikrein binding protein described in serum and other systems. To study a possible relationship between PCI and this kallikrein binding protein we incubated 125I-labeled urinary kallikrein in serum and in PCI-immunodepleted serum in the absence and presence of heparin and analyzed complex formation using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In normal serum, formed complexes co-migrated with complexes of purified PCI and 125I-kallikrein and were less intense in the presence of heparin. No complex formation at all was seen in PCI-depleted serum. Our data indicate that PCI may be a physiologically important endogenous inhibitor of tissue kallikrein and provide evidence that PCI may be identical to the previously described kallikrein binding protein.

Amides↗
PubMed1990

Differential interactions of human kallikrein-binding protein and alpha 1-antitrypsin with human tissue kallikrein.

The characteristics of a new kallikrein-binding protein in human serum and its activities were studied. Both the kallikrein-binding protein and alpha 1-antitrypsin form 92 kDa SDS-stable and heat-stable complexes with human tissue kallikrein. In non-SDS/PAGE, the mobility of these complexes differ. Complex-formation between kallikrein and the binding protein is inhibited by heparin, whereas that between kallikrein and alpha 1-antitrypsin is heparin-resistant. In normal or alpha 1-antitrypsin-deficient-serum, the amount of 92 kDa SDS-stable complex formed upon addition of kallikrein is not related to serum alpha 1-antitrypsin levels. The rate of complex-formation between kallikrein and the binding protein is 12 times higher than that between kallikrein and alpha 1-antitrypsin. Purified alpha 1-antitrypsin, which exhibits normal elastase binding, has a kallikrein-binding activity less than 5% of that of serum. Binding of tissue kallikrein in serum is not inhibited by increasing elastase concentrations, and elastase binding in serum is not inhibited by excess tissue kallikrein. A specific monoclonal antibody to human alpha 1-antitrypsin does not bind to either 92 kDa endogenous or exogenous kallikrein complexes isolated from human serum. The studies demonstrate a new tissue kallikrein-binding protein, distinct from alpha 1-antitrypsin, is present in human serum.

Binding, Competitive↗
PubMed1985

Renal inactive kallikrein as the possible origin of urinary inactive kallikrein in the rat.

An inactive kallikrein, which could be activated with trypsin was isolated from the rat kidney cortex using diethylaminoethyl (DEAE)-cellulose chromatography. The inactive kallikrein had no vasodilator action, whereas the injection of trypsin-activated form of this enzyme into the femoral artery of dogs resulted in a marked increase in the arterial blood flow. Apparent molecular weight of the inactive kallikrein was estimated to be 4.4 X 10(4) by gel filtration, and this enzyme was converted to the renal active kallikrein (M.W. 3.8 X 10(4] by trypsin. The inactive kallikrein is immunologically identical with the trypsin-activated form of inactive kallikrein and active kallikrein. There were no significant differences in the chromatographic behavior on a DEAE-cellulose column, Km value for prolyl-phenylalanylarginine-4-methylcoumaryl-7-amide hydrolysis and profile of inhibition by trypsin inhibitors between the active kallikrein and the trypsin-activated form of inactive kallikrein. The above properties of the renal inactive kallikrein were similar to those of inactive kallikrein found in the urine. These results suggest that the inactive kallikrein in the rat kidney would be proteolytically converted to its active enzyme and that a part of the inactive kallikrein would be excreted into urine in a form itself.

Animals↗
PubMed1980

Isolation and characterization of native single-chain porcine pancreatic kallikrein, another possible precursor of urinary kallikrein.

Porcine pancreatic kallikrein B' was isolated from partially purified prokallikrein B activated "spontaneously" (most probably due to the action of some contaminating proteinase). Upon dodecyl sulfate electrophoresis after reduction, the enzyme migrated like the single-chain alpha-kallikreins A from submandibular glands and urine of the pig, indicating an apparent molecular weight of about 36,000. Evidently, porcine pancreatic kallikrein B' is also a single-chain alpha-kallikrein, in contrast to the two-chain beta-kallikrein obtained by the usual isolation procedure from autolyzed porcine pancreas. The amino acid composition of kallikrein B' is very similar to that of the other porcine glandular kallikreins and it too contains glucosamine. The specific activities of kallikrein B', as measured under various conditions, also resemble closely those of porcine urinary and submandibular kallikreins, as do the rates of the enzyme-catalyzed hydrolyses of various amino acid ester substrates. During the hydrolysis of Bz-LysOMe or low concentrations of Bz-ArgOEt, the same strange biphasic course of the reaction is seen, as observed previously in the case of the other single-chain porcine kallikreins. Consequently, the properties of native porcine pancreatic kallikrein are well consistent with the suggestion that urinary kallikrein represents filtered enzyme of pancreatic and submandibular origin. Further available evidence for this and the alternative hypothesis of synthesis of urinary kallikrein in the kidney is discussed.

Amino Acids↗
PubMed1992

In vivo catabolism of human kallikrein-binding protein and its complex with tissue kallikrein.

We recently identified and purified a novel human kallikrein-binding protein (HKBP) from human plasma. The HKBP forms a 92 kd sodium dodecyl sulfate-stable and heat-stable complex with tissue kallikrein. This study was undertaken to characterize the plasma clearance and tissue distribution of exogenously administered HKBP and its complex with tissue kallikrein. Human tissue kallikrein was first incubated with purified HKBP, and the high-molecular-weight complex was separated from unbound proteins on a high-pressure liquid chromatography gel filtration column. Tissue kallikrein, kallikrein-binding protein, and their complex were labeled with iodine-125 and then injected intravenously into Sprague-Dawley rats. The disappearance rates of trichloracetic acid-precipitable radioactivity from the circulation were determined. The clearance profile of HKBP shows a nonlinear pattern with an apparent half-life of 65 minutes (n = 4). The plasma clearance of HKBP complexed with kallikrein shows a similar profile but a shorter half-life of 33 minutes (n = 3). HKBP and its complex with kallikrein were mainly taken up by the liver but to a lesser degree by the kidney, lung, and other tissues. Labeled human kallikrein has an apparent half-life of 8 minutes (n = 4), and its clearance consists of a fast and a slow component. The data indicate that kallikrein-HKBP complex is cleared from the circulation two times faster than that of the binding protein alone and that it persists in the circulation four times longer than kallikrein alone. The results support the notion that more than one pathway exists for the metabolism of tissue kallikrein and that HKBP plays a role in modulating tissue kallikrein's bioavailability.

Animals↗
PubMed2005

Increased activity of plasma and tissue kallikreins, plasma kininase II and salivary kallikrein in pemphigus foliaceus (fogo selvagem).

BACKGROUND: Pemphigus foliaceus (PF) is an autoimmune blistering disease of unknown aetiology, which is endemic in Brazil. Although the pathogenesis of PF is still unknown, proteins of the contact system have been implicated. OBJECTIVES: As the components of the kinin system may interact with those of the contact system, in this study we evaluated the plasma levels of high-molecular-weight kininogen (HK) and low-molecular-weight kininogen (LK), and the activity of plasma kallikrein, tissue kallikrein and kininase II in plasma of patients with PF presenting with Nikolsky's sign. As kidneys and salivary glands are relevant sources of tissue kallikrein for plasma, we also evaluated urinary/salivary kallikrein and urinary kininase II activities. METHODS: Fifteen patients and 15 age- and sex-matched controls were studied. Kininogen levels were determined by enzyme-linked immunosorbent assay, and the activities of kallikreins and kininase II were determined using selective chromogenic substrates. RESULTS: Compared with controls, plasma HK levels were decreased (P = 0.031), whereas the activities of plasma kallikrein, tissue kallikrein and kininase II in plasma, and the activity of salivary kallikrein, were increased in patients (P < 0.001 for each comparison). Plasma levels of LK and the activities of urinary kallikrein and urinary kininase II were not significantly different from controls. CONCLUSIONS: Diminished levels of HK associated with increased activities of plasma kallikrein and kininase II indicate that the kinin system is activated at the systemic level in PF. As active plasma kallikreins may act on some proteins of the contact system, it is possible that the enzyme may contribute to blister formation. The further observation of an increased tissue kallikrein activity at the systemic and saliva levels may be interpreted as a systemic reflex of skin inflammation. Whether the activation of the kinin system is a cause or a consequence of blister formation needs further clarification.

Adolescent↗
PubMed1986

Immunological identification of rat tissue kallikrein cDNA and characterization of the kallikrein gene family.

A tissue kallikrein cDNA was identified by direct immunological screening with affinity-purified anti-rat tissue kallikrein antibody from a rat submandibular cDNA library constructed with the expression vector pUC8. Sequence analysis of the kallikrein cDNA revealed an encoded protein 97% homologous to the partial amino acid sequence of rat submandibular kallikrein. This cDNA was used to hybrid-select kallikrein-specific RNA from submandibular gland. Translation of the hybrid-selected RNA in a cell-free assay system resulted in the production of a 37 kDa peptide representing the preproenzyme. In addition, hybrid-selection of RNA under less stringent conditions showed cross-hybridization with other submandibular gland mRNA species. In correlation with these results, analysis of rat genomic DNA showed extensive hybridization, suggesting a family of closely related kallikrein-like genes. Consequently, a Charon 4A rat genomic library was screened for kallikrein genes by hybridization with rat tissue kallikrein cDNA. Thirty-four clones were isolated and found to be highly homologous by hybridization and restriction enzymes analyses. Fourteen unique clones were identified by restriction enzyme site polymorphisms within DNA segments which hybridized to the kallikrein cDNA probe and it was estimated that at least 17 different kallikrein-like genes are present in the rat. Sequence and structural analysis of one of the genomic clones revealed a gene structure similar to that of other serine proteinases. Comparison of the partially sequenced exon regions of the gene with the sequence of rat tissue kallikrein cDNA reveals 89% identity when aligned for the greatest homology. However, the genomic sequence predicts termination codons in all three translational reading frames, implying that this gene is nonfunctional, i.e., a pseudogene. Comparison of the rat genomic sequence to a kallikrein-like gene from the mouse reveals extensive preservation of exons, less identity within introns and no significant homology between extragenic regions.

Animals↗
PubMed1987

In vivo effects of camostat mesilate on plasma kallikrein, plasma kininase II and renal kallikrein of man.

N,N-Dimethylcarbamoylmethyl-4-(4-guanidino-benzoyloxy)phenylacetat e methanesulfonate (camostat mesilate) is reported to be an effective inhibitor of plasma kallikrein. It was shown in vitro to inhibit not only plasma kallikrein, but also renal kallikrein and plasma kininase II. These inhibitory activities, however, were very weak. The inhibition of plasma kallikrein in human plasma was limited in time, since a rapid reactivation of plasma kallikrein was noticed when samples were incubated at room temperature. In order to establish whether camostat mesilate was able to inhibit plasma kallikrein, kininase II and renal kallikrein also in vivo the inhibitory activity of camostat mesilate on these enzymes was studied in 5 healthy volunteers. After an oral intake of a single dose of 600 mg of camostat mesilate, plasma kallikrein was inhibited significantly, while kininase II in plasma was unaffected. Renal kallikrein activity determined by urinary excretion of active kallikrein remained unchanged after camostat mesilate intake. Thus, the results demonstrate that camostat mesilate in vivo inhibits only plasma kallikrein and has no effect on the activity of kininase II or renal kallikrein.

Adult↗
PubMed1996

Isolation and characterization of human tissue kallikrein produced in Escherichia coli: biochemical comparison to the enzymatically inactive prokallikrein and methionyl kallikrein.

This report describes bacterial expression, isolation, and characterization of human tissue kallikrein recombinantly produced in Escherichia coli. Successful production of enzymatically active recombinant human kallikrein requires the following processes: expression, solubilization and refolding of prokallikrein, thermolysin activation, and chromatographic separation. All experimental data confirmed that bacterially derived human kallikrein is properly folded and exhibits expected biochemical functions. As confirmed by SDS-PAGE and reverse-phase HPLC, recombinant kallikrein is apparently pure and is devoid of reduced or other partially folded kallikrein forms. Recombinant kallikrein behaves as a monomeric molecule in solution and exhibits full enzymatic activity in hydrolyzing peptide substrates. The molecule can bind to aprotinin to form kallikrein-inhibitor complex at a 1:1 molar ratio. Peptide mapping analysis derived from pepsin digestion of recombinant kallikrein assigned five disulfide bonds which match those of porcine kallikrein predicted from X-ray structure. Peptides containing unpaired cysteines or mispaired disulfide bonds were not detected. Both properly folded prokallikrein and methionyl kallikrein, containing a propeptide and an initiator methionine at their N-termini, respectively, were also produced and isolated. These two molecules are structurally similar to recombinant kallikrein, but are not enzymatically active.

Amino Acid Sequence↗
PubMed1980

Decreased urinary kallikrein activity and elevated blood pressure normalized by orally applied kallikrein in essential hypertension.

Urinary kallikrein excretion was significantly lower in patients with essential hypertension (0.48 +/- 0.05 EU/24 h) than in normotensive controls (1.26 +/- 0.14 EU/24 h). Oral administration of hog pancreatic kallikrein normalized decreased urinary kallikrein and reduced arterial pressure. The treatment-induced rise in urinary kallikrein was due to an enhanced release of endogenous enzyme, as was determined by radioimmunoassay. It is proposed that in the hypertensive patients the low urinary kallikrein excretion reflects a defect in renal kallikrein formation which is normalized by oral kallikrein. The hypotensive action of oral kallikrein as well as its stimulating effects on renal kallikrein release suggest that the kallikrein-kinin system is involved in blood pressure regulation and that impaired renal kallikrein activity may be a factor in the maintenance of essential hypertension.

Adult↗
PubMed1980

Impaired renal kallikrein activity and elevated blood pressure normalized by orally applied kallikrein in essential hypertension.

Urinary kallikrein excretion was significantly lower in patients with essential hypertension (0.48 +/- 0.05 EU/24 h) than in normotensive controls (1.26 +/- 0.14 EU/24 h). Oral administration of hog pancreatic kallikrein normalized decreased urinary kallikrein and reduced arterial pressure. The treatment-induced rise in urinary kallikrein was due to an enhanced release of endogenous enzyme, as was determined by radioimmunoassay. It is proposed that in the hypertensive patients the low urinary kallikrein excretion reflects a defect in renal kallikrein formation which is normalized by oral kallikrein. The hypotensive action of oral kallikrein, as well as its stimulating effects on renal kallikrein release, suggest that the kallikrein-kinin system is involved in blood pressure regulation and that impaired renal kallikrein activity may be a factor in the maintenance of essential hypertension.

Administration, Oral↗
PubMed1979

Low urinary kallikrein excretion and elevated blood pressure normalized by orally kallikrein in essential hypertension.

1. Urinary kallikrein was measured in 67 patients with essential hypertension and 25 normotensive subjects variously on unrestricted and low sodium diet. Also, the effect of orally applied hog pancreatic kallikrein on elevated blood pressure and kallikrein excretion was evaluated. 2. Urinary kallikrein was reduced in a large subgroup of patients with sustained essential hypertension. 3. With salt restriction, urinary kallikrein rose markedly in normotensive subjects and patients with borderline hypertension but not in those with sustained hypertension. 4. Oral kallikrein normalized reduced kallikrein excretion and lowered elevated blood pressure. 5. The rise in urinary kallikrein with oral kallikrein was due to an increased formation of endogenous enzyme. 6. A defective kallikrein-kinin system may be involved in both the low urinary kallikrein excretion and the hypertension.

Administration, Oral↗