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PubMed1975

The behaviour of collagen peptidase in the serum of different dermatoses.

In 150 patients with different dermatoses and 15 controls the activity of collagen peptidase in serum was determined. No relation to specific skin diseases was found. Negative findings were also observed in the group of collagenoses: only 4 of 14 patients with progressive systemic sclerosis showed an increase of this enzyme activity. These negative results seem noteworthy because it thus is demonstrated that alterations of collagen structure are not necessaryly associated with alterations of collagen peptidase activity.

Collagen↗

PubMed1975

Kinetic studies of carboxypeptidase Y. II. Effects of substrate and product analogs on peptidase and esterase activities.

Reversible inhibition of the peptidase and esterase activities of CPase Y [EC 3.4.12.1] was investigated with substrate and product analogs known to be inhibitors or effectors of pancreatic carboxypeptidases A or B [EC 3.4.12.2 or 3]. L-Amino acids and NH2-blocked L-Amino acids showed competitive-type inhibition, whereas their D-enantiomers caused less inhibition than the L-enantiomers, and showed non-competitive or mixed-type inhibition. Some phenylalanine analogs, e.g. beta-phenylpropionic acid and t-cinnamic acid, were also reversible inhibitors of CPase Y. The type of these inhibitors and their K1 values were generally parallel for both the peptidase and esterase activities.

Amino Acids↗

PubMed1990

Kinetic studies of the differential effect of detergents on the peptidase activities of the multicatalytic proteinase from rat liver.

We present here a detailed study of the effect of detergents on the three peptidase activities (hydrolysis of the LLVY, ARR, and LLE peptides) of the purified multicatalytic proteinase from rat liver. At Triton X-100 and sodium dodecyl sulfate (SDS) concentrations of 0.1%, all three peptidase activities are inhibited. Lower concentrations of the two detergents (0.01%) do not affect the hydrolysis of the ARR peptide, whereas they behave differently on the hydrolysis of the LLVY and LLE peptides. Triton X-100 inhibits and SDS strongly activates LLVY peptide hydrolysis by decreasing and increasing Vmax, respectively. In the absence of detergents, the saturation curve for the LLE peptide can be analyzed as the result of two components, one showing cooperative (nH = 1.6) with higher affinity (S0.5 = 60 microM) and lower Vmax than a second, noncooperative component (Km = 320 microM). SDS (0.01%) activates LLE peptide hydrolysis by suppressing cooperativity, slightly increasing Vmax, and decreasing the half-saturation concentration (Km = 30 microM) of the enzyme. Triton X-100 (0.01%) also suppresses the cooperativity and decreases the half-saturation concentration (Km = 25 microM) for the LLE peptide; in contrast, it reduces Vmax by inhibition of the low affinity, high Vmax component observed in the absence of detergents. Based on these observations, it can be concluded that both detergents behave like allosteric activators of peptidylglutamyl-peptide hydrolyzing activity and that the multicatalytic proteinase has at least three different classes of active sites: two independent noncooperative sites that catalyze the hydrolysis of trypsin and chymotrypsin-like substrates and one class for peptidylglutamyl-peptide hydrolysis having two components: one cooperative (two or more sites) and one noncooperative.

Amino Acid Sequence↗

PubMedDate not supplied

Occurrence and potential importance of selected peptidases in bull ejaculates.

The zinc containing peptidases angiotensin-converting enzyme (ACE), neutral metalloendopeptidase (NEP), and leucine aminopeptidase (LAP) occur in bull ejaculates in high activities. These enzyme activities are in close correlation with some routineously determined semen parameters. These ejaculat parameters are used for quality classification and selection of ejaculates and are according to long term experience in good correlation to the male fertility. Semen quality related correlations could not be found for the dipeptidyl aminopeptidase (DPIV) and the aminopeptidase A (APA). Origin and possible function of the zinc containing peptidases in the semen are examined and discussed.

Animals↗

PubMed1985

Identification of prolipoprotein signal peptidase and genomic organization of the lsp gene in Escherichia coli.

The product of the lsp gene of Escherichia coli, i.e. the prolipoprotein signal peptidase, was identified by both in vivo pulse labeling experiments using a high expression lambda PL promoter vector and by an in vitro transcription/translation coupled system. The molecular weight of prolipoprotein signal peptidase was estimated to be approximately 18,000 by its mobility on polyacrylamide gel electrophoresis and was found to be the same as that of SPase II purified from the wild-type cells. Analysis of SPase II activities in strains containing various subclones, deletion derivatives generated from plasmid pMT521, and analysis of protein products in a strain harboring an ileS-lsp-fused gene indicated that ileS and lsp genes are transcribed on the same mRNA. This was further supported by the observation that Tn5 insertions in the ileS gene resulted in a reduced expression of the lsp gene. In addition to an upstream promoter shared by the ileS and lsp genes, these analyses also revealed the presence of an internal promoter for the lsp gene within the coding region of the ileS gene.

Bacterial Outer Membrane Proteins↗

PubMed1989

Solubilization and characterization of yeast signal peptidase.

An efficient post-translational assay for solubilized yeast signal peptidase has been developed. The enzyme can be solubilized in nonionic detergent (0.5% Nikkol) without added salt, but salt increased the efficiency of solubilization. Radiosequencing of the cleaved substrate revealed that the enzyme removed the signal peptide. The substrate (prepro-alpha-factor) must be pretreated with sodium dodecyl sulfate to be cleaved. The enzyme displays a broad, alkaline pH optimum, retaining activity at pH 12. Moderately high temperatures (35 degrees C), excess detergent (greater than 0.5% Nikkol), or high salt (greater than 300 mM KOAc) will inactivate the enzyme. Phosphatidylcholine is necessary for optimal activity. The optimal ratio of Nikkol:lipid:sodium dodecyl sulfate is 6.4:2.2:1. The membrane association of yeast signal peptidase is resistant to carbonate extraction, indicating that it is an integral membrane protein.

Endopeptidases↗

PubMed1989

[BANA hydrolase and DNP peptidase activities in the ovulatory process of PMS-hCG treated immature rat].

To investigate the roles of collagenolytic enzymes in the ovulatory process of PMS-hCG treated immature female rats (22 days old), we measured the activities of two of them in the ovary by the using synthetic substrates alpha-N-benzoyl-DL-arginine-2-naphthylamide HCl (BANA) (a collagenolytic cathepsin) and dinitrophenol-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg OH (DNP peptide) (a neutral collagenase). BANA hydrolase activities significantly began to increase after the hCG injection, reaching a peak 8-9 hours later, and then decreased sharply 10 hours later. There was also a significant increase in DNP peptidase activities 7-10 hours after the hCG injection and a significant decrease 12 hours after the injection. The present study has shown that BANA hydrolase and DNP peptidase appear during the ovulatory process of PMS-hCG-treated immature female rats, and that their significant preovulatory increases are contributory to collagenolysis in follicle rupture.

Animals↗

PubMed1988

cDNA-derived primary structure of the glycoprotein component of canine microsomal signal peptidase complex.

Canine microsomal signal peptidase activity has been shown previously to co-migrate as an apparent complex of six polypeptides with molecular masses of 25, 23, 22, 21, 18, and 12 kDa. The 22- and 23-kDa species are differentially glycosylated forms of the same protein, designated SPC 22/23. The amino acid sequence of SPC 22/23 was deduced from cDNA clones. The protein is synthesized without a cleavable amino-terminal signal sequence and contains a single site for N-linked glycosylation. SPC 22/23 appears to be anchored to the rough endoplasmic reticulum membrane by a single hydrophobic segment near its amino terminus, with the remainder of the protein positioned on the lumenal side of the membrane. The amino acid sequence of SPC 22/23 shares homology with tryptic peptides derived from the hen oviduct signal peptidase glycoprotein, one of two possible proteins required for signal peptide processing in the avian system (Baker, R.K., and Lively, M.O. (1987) Biochemistry 26, 8561-8567). Therefore, the complete amino acid sequence of SPC 22/23 presented in this report corresponds to one of two possible proteins required for signal peptide processing in higher eukaryotic cells.

Amino Acid Sequence↗

PubMed1988

Metabolism of angiotensins II and III by membrane-bound peptidases from rat brain.

This study examines the metabolism of 125I-angiotensin II (125I-ANG II) and 125I-angiotensin III (applied 125I-ANG III or 125I-ANG IIIapp) by membrane peptidases. The first step in the metabolism of 125I-ANG II was the formation of 125I-ANG III (generated 125I-ANG III or 125I-ANG IIIgen). The ability of both ANG II and ANG III to reduce 125I-ANG IIIgen production without ANG(1-5), ANG(2-5), amastatin or bestatin being similarly effective suggests that this step may be highly substrate-specific. Subsequent metabolism of 125I-ANG IIIgen was similar to that of 125I-ANG IIIapp in that 125I-ANG(2-7) and 125I-ANG(2-4) fragments were produced. The formation of 125I-ANG(2-7) appeared to be a very substrate-specific process because it was only inhibited by ANG II and ANG III. In contrast, the production of 125I-ANG(2-4) was unaffected at the concentration of inhibitors used and is considered to be a relatively nonspecific process. However, despite these similarities sequential N-terminal cleavage leading to the formation of 125I-ANG(3-8), 125I-ANG(4-8) and 125I-Tyrosine appears to be the preferred pathway in the metabolism of 125I-ANG IIIapp. The absence of this pathway in the metabolism of 125I-ANG IIIgen suggests that applied and generated 125I-ANG III may be metabolized in separate degradative compartments. These data demonstrate that 125I-ANG II and 125I-ANG III are metabolized by membrane-bound peptidases in an orderly and sequential manner.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗

PubMed1987

Collagen peptidase in serum of patients with myocardial infarction.

Activity of collagen peptidase was measured in patients with myocardial infarction. Determinations were carried out 1, 3, 6, 9, 14 and 21 days after admission to the hospital. A decrease of activity was observed between the 6th-21st day of the disease. A low correlation with serum aminotransferases was found. It is concluded that estimation of serum collagen peptidase does not reflect accumulation of collagen in the healing heart muscle.

Adult↗

PubMed1986

Deletion of the propeptide from human preproapolipoprotein A-II redirects cotranslational processing by signal peptidase.

The functions of NH2-terminal propeptides are not known. We have used apoA-II as a model to study prosegment structure/function relationships. The primary translation product of human apolipoprotein A-II mRNA contains an 18-amino acid signal peptide, a 5-amino acid propeptide, and the mature 77-amino acid plasma protein sequence. Its propeptide was deleted by site-directed mutagenesis of a cloned cDNA. The effects of this mutation on cotranslational translocation and proteolytic processing were assessed using an in vitro transcription/translation/microsomal membrane processing system. Deletion of the propeptide did not affect cotranslational translocation. However, without its propeptide, signal peptidase cleavage was redirected to a different site located between the 2nd and 3rd residues of the mature protein. Since the primary structure of the signal peptide was not altered in the mutant, these results suggest that sequences located downstream from the signal peptidase cleavage site (e.g. in propeptides) may modulate, or participate in defining, the correct site of cotranslational proteolytic processing.

Apolipoproteins A↗

PubMed1985

Inhibition of prolipoprotein signal peptidase by globomycin.

Globomycin inhibits the prolipoprotein-specific signal peptidase activity by binding to the enzyme in a noncompetitive manner (Ki = 36 nM). The Km of prolipoprotein signal peptidase for the prolipoprotein substrate is 6 (+/- 1) microM.

Anti-Bacterial Agents↗

PubMed1982

Identification of the signal peptidase cleavage site in Bacillus licheniformis prepenicillinase.

The DNA sequence of the entire gene for penicillinase of Bacillus licheniforms 749 has recently been determined (Neugebauer, K., Sprengel, R., and Schaller, H. (1981) Nucleic Acid Res. 9, 2577-2588). Here we show that a primary translation product (Mr 35,000) can be synthesized in vitro by translation of B. licheniformis mRNA in a EScherichia coli cell-free system, or in vivo, after phenylethyl alcohol treatment of B. licheniformis. The partial NH2-terminal sequence of the in vivo synthesized primary translation product, termed prepenicillinase, was in agreement with the NH2-terminal sequence deduced from the DNA sequence. Furthermore, when a B. licheniformis membrane fraction plus the nonionic detergent Nikkol were present in the in vitro translation system, prepenicillinase was proteolytically processed to a polypeptide (Mr 31,250) that comigrated electrophoretically with the membrane-bound form of this enzyme. The partial NH2-terminal sequence of this processed form showed that it had lost 26 NH2-terminal residues present in prepenicillinase. We propose that the observed cleavage was due to membrane-associated and detergent-activated signal peptidase and consequently, that the 26-residue-long extension of nascent prepenicillinase functions in translocation across the prokaryotic plasma membrane. Based on our partial protein sequence data and the DNA sequence data, the signal peptidase-processed penicillinase starts with a Cys residue. Cotranslational and post-translational modifications of this NH2-terminal Cys, similar to those observed in the E. coli lipoprotein, might be the only means by which penicillinase can be anchored to the outer leaflet of the B. licheniformis plasma membrane.

Amino Acid Sequence↗

PubMed1984

Action of peptidase inhibitors on methionine5-enkephalin-arginine6-phenylalanine7 (YGGFMRF) and methionine5-enkephalin (YGGFM) metabolism and on electroacupuncture antinociception.

In the spinal cord Met5-enkephalin-Arg6-Phe7 (YGGFMRF) is located in small interneurons of the dorsal and ventral horns. From these storage sites, YGGFMRF can be released by perfusing the subarachnoidal spaces of the spinal cord with artificial spinal fluid containing substance P. In vitro YGGFMRF can be hydrolyzed readily by a dipeptidyl carboxypeptidase. In order to ascertain whether this reaction is physiologically relevant, we measured the content of YGGFMRF and Met5-enkephalin (YGGFM) in subarachnoidal space perfusate in presence and in absence of captopril, bestatin and thiorphan using substance P to activate the release of opioid peptides. Without peptidase inhibitors, the efflux of YGGFMRF and YGGFM was hardly detectable. The addition of captopril to the perfusion medium increased the substance P (10(-7) M)-induced release of YGGFMRF markedly but it increased the efflux of YGGFM to a much smaller extent. When captopril and bestatin were added together the amount of YGGFMRF present in the perfusate was further increased slightly. In contrast, the YGGFM content in the same perfusate was increased greatly by bestatin and only slightly by thiorphan. To characterize the pharmacological profile of these peptidase inhibitors, we compared electroacupuncture antinociception with and without intrathecal injections of captopril and bestatin. This antinociception, as measured by tail-flick latency, was potentiated by the intrathecal injection of captopril and bestatin. These results taken together suggest that YGGFMRF released in the perfusate of the arachnoidal space by substance P is metabolized by both dipeptidyl carboxypeptidase and aminopeptidase.

Acupuncture Therapy↗

PubMed1984

[The peptidase site of butyrylcholinesterase is distinct from the esterase site].

Highly purified human plasma butyrylcholinesterase was inhibited by reversible inhibitors of esterase activity and modified by active-site-directed irreversible inhibitors of esterases and proteases. Peptidase and esterase activities of inhibited enzyme were simultaneously essayed from rates of hydrolysis of substance P (first cleavage) and butyrylthiocholine respectively. Inhibition parameters values and rates of inactivation of the two activities provide evidence that the peptidasic site is distinct from the esteratic site.

Binding Sites↗

PubMed1983

Neurotensin analogs [D-TYR11] and [D-PHE11]neurotensin resist degradation by brain peptidases in vitro and in vivo.

The present study was designed to compare the susceptibility of neurotensin (NT), [3H]NT, [D-Tyr11]NT and [D-Phe11]NT to degradation by 1) rat brain synaptic membranes in vitro and 2) after i.c.v. administration in the rat in vivo. Degradation was assessed by purifying the peptides using reverse phase high-performance liquid chromatography and by measuring the amount of radioactive or absorbing (OD 230) material under each peptide peak. In contrast to NT, [D-Tyr11]NT and [D-Phe11]NT were resistant to degradation by brain synaptic peptidases in vitro. Furthermore, NT was rapidly metabolized in brain tissues after i.c.v. administration, whereas [D-Tyr11]NT was metabolically stable. The present data confirm the central role of NT residue Tyr11 in the mechanisms of NT inactivation by brain synaptic peptidases. They account for the higher in vivo potency of [D-Tyr11]NT as compared with its in vitro potency. Finally, they explain, at least in part, the need to administer large doses of NT in the brain in order to observe neurobehavioral and neuropharmacological effects.

Animals↗

PubMed1980

Epidermal growth factor, renin, and peptidase in cultured tumor cells of submandibular gland origin.

Dimethylbenz[a]anthracene was injected into the submandibular glands of male Swiss-Webster mice. From tumors obtained, three cell lines were established. Immunocytochemical stainings revealed epidermal growth factor, renin, and peptidase in a significant portion of cultured tumor cells. In addition, the presence of epidermal growth factor was demonstrated by radioimmunoassays. Since epidermal growth factor, renin, and peptidase are localized in the granular convoluted tubules in mouse submandibular gland, the data suggest that the granular convoluted tubule cells are the targets of chemical carcinogens.

Animals↗

PubMed1994

Characterization of a novel high molecular mass protein with peptidase activity purified from the human erythrocyte membrane by calmodulin affinity chromatography.

A previously undescribed high molecular mass protein (HMP) from human erythrocyte membranes was solubilized by Triton X-100 and purified on a calmodulin-agarose column in the presence of Ca2+. It was shown to have a native molecular mass of 522-560 kDa, comprised of a single subunit of a molecular mass of 28 kDa (p28). The protein is associated with the lipid bilayer rather than with the cytoskeletal component of the membrane. The purified HMP showed peptidase-hydrolyzing activity toward substrates containing hydrophobic amino acids at the P1 position of the P2-P1 cleavage site. The activity was inhibited by serine proteinase inhibitors (leupeptin, phenylmethansulfonyl fluoride) and chymotrypsin inhibitors in particular (chymostatin, N-tosyl-L-phenylalanine chloromethyl ketone). The enzyme exhibited maximal activity at slightly alkaline pH (7.5-8.5) and at 37 degrees C and was stimulated over a narrow range of SDS concentrations (maximal at 0.05%). HMP was found to cross-react in Western blots with an antibody raised against the rabbit multicatalytic proteinase. The single subunit of HMP therefore contains both the catalytic activity and a sequence necessary for its association into a multimeric complex. The properties of the human erythrocyte membrane HMP described indicate that it is a novel peptidase related to the ubiquitous multicatalytic proteinase.

Amino Acid Sequence↗