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H Kirschke

Publications and source records attributed to H Kirschke.

At least 37 records · Page 2Linked to original sources
PubMed1993

Functional expression of human cathepsin S in Saccharomyces cerevisiae. Purification and characterization of the recombinant enzyme.

A cDNA encoding the human lysosomal cysteine proteinase cathepsin S precursor has been expressed in yeast using the pVT100-U expression vector containing the alpha-factor promoter. The procathepsin S gene was expressed either as a fusion protein with the pre-region or with the prepro-region of the yeast alpha-factor precursor gene. Following in vitro processing both constructs gave an identical active mature enzyme with a molecular weight of 24,000. After prolonged cultivation of the cells the recombinant protein is also found as an active proteinase in the culture supernatant. The precursor can be activated in vitro at pH 4.5 and 40 degrees C under reducing conditions. The in vitro activated enzyme has a 6-amino acid NH2-terminal extension when compared with the native bovine enzyme. The purified enzyme displays a bell-shaped pH activity profile with a pH optimum of 6.5 and pK values of 4.5 and 7.8. The isoelectric point of the recombinant human cathepsin S is between 8.3 and 8.6 and about 1.5 pH units higher than for the bovine enzyme. The kinetic data for several synthetic substrates and inhibitors reveal a preference for smaller amino acid residues in the binding subsites S2 and S3 of cathepsin S. Like the bovine enzyme, the recombinant human cathepsin S is characterized by a broader range of pH stability (pH 5-7.5) than cathepsins B and L.

Base Sequence↗
PubMed1993

Secretion of a latent, acid activatable cathepsin L precursor by human non-small cell lung cancer cell lines.

Secretion of pro-cathepsin L, the precursor of a lysosomal cysteine proteinase, has been described for ras-transfected mouse fibroblasts and several human cancer cell lines. The secretion of a latent but stable precursor might be a means for tumor cells to involve this proteinase in extracellular matrix breakdown. Since lung cancer is the leading cause of cancer death in the industrialized countries, we therefore studied the secretion of pro-cathepsin L in 11 human non-small cell lung cancer cell lines (EPLC 32M1, NCI H157, EPLC 272H, U1752, LCLC 103H, LCLC 97TM1, U 1810, NCI H661, NCI H23, NCI H125, and NCI H596) and 8 human small cell lung cancer cell lines (SCLC 22H, NCI H60, NCI H82, NCI H526, NCI H146, NCI H841, NCI H510, and DMS 79). Immunoblot analysis of cell conditioned media showed that latent pro-cathepsin L (M(r) 42 kDa) was secreted in all 11 non-small cell lung cancer cell lines. Three of these cell lines secreted an additional inactive form of cathepsin L of M(r) 24 kDa. In contrast, the 8 small cell lung cancer cell lines did not secrete any detectable cathepsin L-immunoreactive material. Phorbol-12-myristate-13-acetate increased the secretion of pro-cathepsin L in 6 of the non-small cell lung cancer cell lines. The cathepsin L precursor could be activated in vitro at pH 3, accompanied by a shift in molecular mass to 34 kDa. Chicken egg white cystatin prevented the acid activation. Specific antibodies against a synthetic peptide from the pro-sequence of cathepsin L reacted with the nonsmall cell lung cancer cathepsin L precursor. Extracellular pro-cathepsin L may be important in the tumor biology of non-small cell lung cancer and would be a good target for novel diagnostic and therapeutic approaches, since the majority of physiological lysosomal proteinases are contained in intracellular compartments only.

Adenocarcinoma↗
PubMed1992

Phylogenetic conservation of cysteine proteinases. Cloning and expression of a cDNA coding for human cathepsin S.

A 1.8-kilobase full-length cDNA of human cathepsin S, a lysosomal cysteine proteinase, has been isolated. The single long open reading frame encodes a polypeptide of 331 amino acids consisting of a 15-amino acid NH2-terminal signal peptide, a propeptide of 99 amino acids, and a mature polypeptide of 217 amino acids. The deduced amino acid sequence contains only one potential N-glycosylation site located in the propeptide. The NH2-terminal amino acid sequence of the mature polypeptide was confirmed by sequencing cathepsin S purified from human spleen. The cDNA detects a 1.9-kilobase transcript in poly(A)+ RNA from human fibroblasts. Expression of human cathepsin S in transfected baby hamster kidney cells resulted in up to more than 300-fold cathepsin S activity as compared to untransfected controls. In the expressing baby hamster kidney cells, human cathepsin S is transported to the lysosomes via the mannose 6-phosphate receptor pathway as shown by density gradient centrifugation, immunofluorescence, and detection of the 37-kDa cathepsin S precursor in the medium in the presence of NH4Cl. The deduced amino acid sequence of human cathepsin S exhibits a substantial degree of similarity with other human cysteine proteinases and papain indicating that they have a common ancestral gene and are members of a gene family.

Amino Acid Sequence↗
PubMed1992

Lysosomal proteinases as putative diagnostic tools in human neuropathology: Alzheimer disease (AD) and schizophrenia.

The cathepsin B, D and L were studied by immunohistochemical techniques in the human postmortem brain. The enzyme were primarily localized in neurons. Makroglial cells were seldom immunostained. It is shown that cathepsins B and D frequently occur in neuritic plaques of Alzheimer victims, thereby raising the question, whether or not cathepsin immunohistochemistry is a useful tool in the diagnosis of this disease. Furthermore, we identified certain glial cells to be immunoreactive for cathepsins in schizophrenics.

Aged↗
PubMed1991

Primary structure of bovine cathepsin S. Comparison to cathepsins L, H, B and papain.

The primary structure of bovine cathepsin S was determined by combining results of protein and peptide sequencing with the sequence deduced from nucleic acid sequencing. Using polymerase chain reaction (PCR) technology, cDNA clones commencing at amino acid 22 of the mature enzyme and continuing through the 3' untranslated region of bovine cathepsin S mRNA were isolated and sequenced. The open reading frame in these overlapping clones correctly predicts the determined amino acid sequence of 13 tryptic peptides derived from purified bovine spleen cathepsin S. The deduced amino acid sequence shows that mature bovine cathepsin S consists of 217 amino acids corresponding to a molecular weight of 23.7 kDa. Cathepsin S belongs to the papain superfamily of lysosomal cysteine proteinases and shares 41% identity with papain. Amino acid sequence identities of bovine cathepsin S to human cathepsins L, H, and B are 56%, 47% and 31% respectively.

Amino Acid Sequence↗
PubMed1991

Ultrastructural study of cathepsin B immunoreactivity in rat brain neurons: lysosomal and extralysosomal localizations of the antigen.

Cathepsin B was localized in multiple neurons of the rat central nervous system by means of the peroxidase-antiperoxidase technique and immunogold labeling using a polyclonal antiserum produced in rabbits against rat liver enzyme. The main intracellular locus of cathepsin B antigenic sites was in lysosomes. In some cases, however, immunoreactive material was also detected outside lysosomes (i.e. at the membranes of the rough endoplasmic reticulum). The findings are discussed with respect to the proposed role of the enzyme in the general protein metabolism of the brain and the potency of the antiserum to label the proform of cathepsin B.

Animals↗
PubMed1991

Tight-binding inhibition of cathepsin S by cystatins.

Human cystatins A, B and C were purified, and their inhibition efficiency was tested with the cysteine proteinase cathepsin S. Cathepsin S was strongly inhibited by cystatins A and B in the subnanomolar range and by cystatin C in the picomolar range. Two steps of inhibition of cathepsin S by the cystatins which involve slow binding are discussed.

Amino Acid Sequence↗
PubMed1990

Chromogranin A-processing proteinases in purified chromaffin granules: contaminants or endogenous enzymes?

It was the purpose of this study to define the chromogranin A-processing proteinases present in highly purified preparations of bovine chromaffin granules. The most active enzyme had a pH optimum of 5.0 and was inhibited by pepstatin. It could be identified immunologically as a cathepsin D-like enzyme and subcellular fractionation established its lysosomal origin. After removal of this enzyme the remaining activity at pH 5.0 was mainly due to a cathepsin B-like proteinase. The presence of this enzyme could also be attributed to lysosomal contamination. In the presence of calcium, a further proteolytic activity became apparent at pH 5.0. This enzyme which was inhibited by rho-chloromercuriphenylsulfonic acid was localized in chromaffin granules. A trypsin-like peptidase, most active at pH 8.2, was enriched in a membrane wash of chromaffin granules. Subcellular fractionation indicated that this enzyme is preferentially bound to the membranes of very dense particles probably representing a subpopulation of chromaffin granules. This study establishes that the most active chromogranin A-degrading proteinases present in highly purified chromaffin granules are attributable to lysosomal contamination. Two enzymes with low activity (a Ca2+ activated proteinase and a trypsin-like enzyme) are, apparently, true constituents of chromaffin granules.

4-Chloromercuribenzenesulfonate↗
PubMed1990

Antigenic expression of cathepsin B in aged human brain.

The lysosomal thiol proteinase, cathepsin B, has been localized in different regions of aged human brain by use of the peroxidase-antiperoxidase technique. Cathepsin B-immunoreactive material was detected in multiple neurons of human hippocampus, neocortical area A 10, prefrontal gyrus and nuc. basalis of Meynert as well as in single white matter astrocytes. In brains of Alzheimer disease-affected subjects cathepsin B was revealed in neuritic plaques too. Possible functional consequences with regard to normal aging, neuropeptide metabolism and pathological changes are discussed.

Aged↗
PubMed1990

Localization and activity of various lysosomal proteases in Leishmania amazonensis-infected macrophages.

In mammalian hosts, Leishmania amastigotes are obligatory intracellular parasites of macrophages and multiply within parasitophorous vacuoles of phagolysosomal origin. To understand how they escape the harmful strategies developed by macrophages to kill ingested microorganisms, it is important to obtain information on the functional state of parasitophorous vacuole. For this purpose, we studied the intracellular distribution and activity of host lysosomal proteases in rat bone marrow-derived macrophages infected with Leishmania amazonensis amastigotes. Localization of cathepsins B, H, L, and D was investigated by using specific immunoglobulins. In uninfected macrophages, these enzymes were located in perinuclear granules (most of them were probably secondary lysosomes) which, after infection, disappeared progressively. In infected macrophages, cathepsins were detected mainly in the parasitophorous vacuoles, suggesting that the missing secondary lysosomes had fused with these organelles. Biochemical assays of various proteases (cathepsins B, H, and D and dipeptidyl peptidases I and II) showed that infection was accompanied by a progressive increase of all activities tested, except that of dipeptidyl peptidase II, which remained constant. No more than 1 to 10% of these activities could be attributed to amastigotes. These data indicate that (i) Leishmania infection is followed by an increased synthesis and/or a reduced catabolism of host lysosomal proteases, and (ii) amastigotes grow in a compartment rich in apparently fully active proteases. Unexpectedly, it was found that infected and uninfected macrophages degraded endocytosed proteins similarly. The lack of correlation in infected macrophages between increase of protease activities and catabolism of exogenous proteins could be linked to the huge increase in volume of the lysosomal compartment.

Animals↗
PubMed1989

Cathepsin S from bovine spleen. Purification, distribution, intracellular localization and action on proteins.

Cathepsin S was detected in bovine kidney, spleen, lymph nodes and lung by immunochemical methods. The immunostaining of cathepsin S in kidney was concentrated to the cells of the proximal tubule, where the enzyme was present in cytoplasmic granules. The purification method for cathepsin S from bovine spleen involved (NH4)2SO4 fractionation, chromatography on CM-Sephadex C-50, gel filtration on Sephacryl S-200 and chromatofocusing (pH 8.0-6.0). The enzyme was partially destroyed by autolysis of the homogenate at pH 4.2. The isoelectric point of cathepsin S was 7.0. Cathepsin S was found to hydrolyse proteins at a similar rate to cathepsin L below pH 7.0. At pH values of 7.0-7.5 cathepsin S retained most of its activity, whereas cathepsin L was completely inactive.

Animals↗
PubMed1989

The specificity of bovine spleen cathepsin S. A comparison with rat liver cathepsins L and B.

The peptide-bond-specificity of bovine spleen cathepsin S in the cleavage of the oxidized insulin B-chain and peptide methylcoumarylamide substrates was investigated and the results are compared with those obtained with rat liver cathepsins L and B. Major cleavage sites in the oxidized insulin B-chain generated by cathepsin S are the bonds Glu13-Ala14, Leu17-Val18 and Phe23-Tyr26; minor cleavage sites are the bonds Asn3-Gln4, Ser9-His10 and Leu15-Tyr16. The bond-specificity of this proteinase is in part similar to the specificities of cathepsin L and cathepsin N. Larger differences are discernible in the reaction with synthetic peptide substrates. Cathepsin S prefers smaller neutral amino acid residues in the subsites S2 and S3, whereas cathepsin L efficiently hydrolyses substrates with bulky hydrophobic residues in the P2 and P3 positions. The results obtained from inhibitor studies differ somewhat from those based on substrates. Z-Phe-Ala-CH2F (where Z- represents benzyloxycarbonyl-) is a very potent time-dependent inhibitor for cathepsin S, and inhibits this proteinase 30 times more efficiently than it does cathepsin L and about 300 times better than it does cathepsin B. By contrast, the peptidylmethanes Z-Val-Phe-CH3 and Z-Phe-Lys(Z)-CH3 inhibit competitively both cathepsin S and cathepsin L in the micromolar range.

Amino Acid Sequence↗
PubMed1989

Potent and selective inactivation of cysteine proteinases with N-peptidyl-O-acyl hydroxylamines.

A series of N-peptidyl-O-acyl hydroxylamines was synthesized and tested as inactivators of cysteine proteinases. Depending on the structure of the peptidyl residue of the inhibitors, rapid and complete irreversible inactivation of the lysosomal cathepsins, B, L and S, may be achieved. The most effective inhibitors display second-order rate constants of the inactivation in the range 10(5)-10(6) M-1.s-1. By contrast, the activity of the aminoendopeptidase cathepsin H is only negligibly affected by the N-terminal-protected peptidyl inhibitors.

Amino Acid Sequence↗
PubMed1989

The inactivation of the cysteinyl exopeptidases cathepsin H and C by affinity-labelling reagents.

An attempt has been made to extend to the cysteinyl exopeptidases cathepsins H and C affinity-labelling approaches shown to be effective with cysteinyl endopeptidases such as cathepsins B and L and the calcium-activated proteinase. This involved the preparation of amino acid and dipeptide derivatives with unblocked N-termini to satisfy the aminopeptidase and dipeptidyl aminopeptidase characteristics of cathepsins H and C respectively. For covalent reactivity, the possibilities examined included diazomethanes (-CHN2), fluoromethanes (-CH2F) and dimethylsulphonium salt [-CH2S+(CH3)2]. A dipeptidylfluoromethane with a free amino group could not be prepared, perhaps due to inherent instability. Cathepsin H was inactivated by 1 microM-H2N-Phe-CH2F (the 'H2N' indicates a free unblocked amino group) (k2 = 1878 M-1.s-1); this reagent was without effect on cathepsins C and B, even at 100-fold this concentration. Analogous selectivity was shown by H2N-Ser(OBzl)-CHN2 and H2N-Phe-CH2S+(CH3)2, members of other classes of covalently binding reagents. For cathepsin C the dipeptide derivatives H2N-Gly-Phe-CHN2 and H2N-Phe-Ala-CH2S+(CH3)2 caused rapid inactivation near 10(-7) M. Higher concentrations inactivated cathepsins H and B, but the rates were slower by two to three orders of magnitude than for cathepsin C.

Affinity Labels↗
PubMed1989

The processing of a cathepsin L precursor in vitro.

Subcultured rat fibroblasts secreted a cathepsin L precursor when maintained for 24 h in serum-free medium containing 20 mM ammonium ions. The precursor was identified by immunoblotting after sodium dodecyl sulfate-polyacrylamide gel electrophoresis using polyclonal antibodies to cathepsin L. The molecular mass of the precursor was found to be approximately 39 kDa, which confirms the result originally reported by Y. Nishimura et al. (1988, Arch. Biochem. Biophys. 263, 107-116). Treatment of the precursor containing medium with cathepsin D at pH values ranging from 3.5 to 5.5 caused a limited cleavage of the precursor molecule. The resultant polypeptides are an unstable intermediate form with Mr 35,000 and a stable single chain form of cathepsin L showing a Mr about 32,500. The cathepsin D-mediated conversion was strongly accelerated by Hg2+ ions. A further proteolytic cleavage of the 32.5-kDa polypeptide has not been observed. The enzymatic activity toward Z-Phe-Arg-NHMec at pH 5.5 increased during the conversion, indicating that active cathepsin L was formed from an inactive precursor molecule.

Animals↗
PubMed1989

ATP-activated, high-molecular-mass proteinase-I from rat skeletal muscle is a cysteine proteinase-alpha 1-macroglobulin complex.

From rat skeletal muscle tissue we have isolated and purified a proteolytic activity of molecular mass 750 kDa. The enzyme, designated 'proteinase I', which has been found to be located in capillaries of skeletal muscle tissue, catalyzes the hydrolysis of Z-Phe-Arg-MCA and [14C]methylcasein and this process is activated about 2-fold by ATP. As judged by SDS-polyacrylamide gel electrophoresis the subunit pattern of 'proteinase I' is similar to alpha-macroglobulin. Immunoelectrophoretic analyses of 'proteinase I' with antisera to rat alpha 1-macroglobulin, alpha 2-macroglobulin, and rat liver cathepsins reveal that this high-molecular-mass proteinase is a complex of alpha 1-macroglobulin and the cysteine proteinases cathepsin B, H and L. A similar 'proteinase' has been isolated from rat serum. Two ATP-activated high molecular-mass proteinases that have been previously identified in liver and heart muscle by other investigators equally show a positive immunological reaction with the antiserum raised against 'proteinase I'. From these data, together with results presented in an accompanying paper (Kuehn, L., Dahlmann, B., Gauthier, F. and Neubauer, H.-P. (1989) Biochim. Biophys. Acta 991, 263), we conclude that the ATP-stimulated high-molecular-mass proteolytic activity is partly due to the presence of a complex of alpha-macroglobulin and cysteine proteinases.

Adenosine Triphosphate↗
PubMed1989

Cell type-specific distribution of cathepsin B and D immunoreactivity within the rabbit retina.

The cellular localization of cathepsin B and D immunoreactivity was demonstrated at the light microscopic level in the retina of adult rabbits by use of the peroxidase-antiperoxidase technique. Antisera were raised against rat liver enzymes. Whereas cathepsin D immunoreactivity was confined to Müller (glial) cells, cathepsin B was demonstrated in some, but not all, neuronal cell types. It is proposed that the two enzymes might carry different functions within the neuronal versus glial compartment.

Animals↗