Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CATHEPSIN”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1996

Hybrids of chicken cystatin with human kininogen domain 2 sequences exhibit novel inhibition of calpain, improved inhibition of actinidin and impaired inhibition of papain, cathepsin L and cathepsin B.

Chicken cystatin and human kininogen domain 2 are members of the cystatin superfamily of protein-type cysteine proteinase inhibitors. They show structural and functional similarities, but only human kininogen domain 2 inhibits calpain. Using recombinant chicken cystatin as a scaffold for hybrid cassette analysis, the known reactive-site regions (N-terminus, first hairpin loop and second hairpin loop) were substituted by the corresponding sequences of human kininogen domain 2 in a single and combined manner. Seven hybrids were expressed, purified to homogeneity, characterized protein-chemically, and their inhibition of papain, actinidin, human cathepsin B, human cathepsin L and calpain (80-kDa subunit of rabbit skeletal muscle calpain II and porcine erthrocyte calpain 1) was determined. Strong but temporary inhibition of calpain by chicken cystatin hybrids carrying the N-terminus alone (variant sc1-KD2) or the N-terminus together with the first hairpin loop (variant sc1/2-KD2) was observed; hybrids of the second hairpin loop (sc3-KD2, sc1/3-KD2, sc2/3-KD2, sc1/2/3-KD2) were less strong calpain inhibitors. These data indicate that the inhibiton of calpain by human kininogen domain 2 requires the correct conformation and combination of several contact sites, and suggest that the N-terminus and the first hairpin loop play a major role in this ensemble. Remarkably, hybrid sc2-KD2 exhibited 5 or 150 times stronger inhibition of actinidin compared to native chicken cystatin or to proteolytically isolated human kininogen domain 2, respectively. This indicates an important role of the first hairpin loop of cystatins in the interaction with actinidin. Along with the impaired inhibition of cathepsin L, papain, actinidin, cathepsin B and calpain by the hybrids sc1/3-KD2, sc2/3-KD2 and sc1/2/3-KD2, these results support our hypothesis that all three predicted contact regions of kininogen domain 2 contribute to binding in the active-site clefts of papain-like enzymes in a finely balanced manner.

Amino Acid Sequence↗
PubMed1985

Sodium salicylate activates cathepsin B but not cathepsin H from rat spleen.

Effect of sodium salicylate (SA) and its analogues on lysosomal cysteine proteinases, cathepsins B and H, was investigated. Using a sensitive fluorometric assay, SA was shown to activate cathepsin B but not cathepsin H in the presence of cysteine. Kinetics data showed that the SA-stimulated reaction was due to a 4.5-fold decrease in Km. SA caused a decrease in the inactivation rate of cathepsin B by leupeptin and E-64. It was suggested that SA stimulates the activation process of the essential cysteine residue.

Animals↗
PubMed1996

Activation of cathepsin B, secreted by a colorectal cancer cell line requires low pH and is mediated by cathepsin D.

The aim of our study was to identify changes in secreted procathepsin B levels in a model of the human colorectal adenoma to carcinoma sequence and to determine the factors required for its extracellular activation. Conversion of the non-tumorigenic adenoma-derived cell line PC/AA to a highly tumorigenic phenotype (designated AA/CI/SB10/M) was associated with an 8-fold increase in the presence of the proform of cathepsin B in 24 hr conditioned serum-free medium (SFM). In addition, mature enzyme was only detected in the cell lines of this model with increased malignant potential. This is in agreement with the findings of a previous study, in which mature cathepsin B was only present in the 24 hr conditioned SFM of cancer-derived cell lines and not in SFM from adenoma-derived cell lines. Having demonstrated a reduction in the pH of conditioned medium from cell lines with increased malignant potential, we used a range of specific proteinase inhibitors to show that an aspartyl proteinase was involved in the initial activation of procathepsin B. Consistent with this finding, we subsequently demonstrated an increased secretion of the aspartyl proteinase cathepsin D in the medium of the AA/CI/SB10/M adenocarcinoma cells compared with the non-tumorigenic AA/Cl cell line. Therefore, the presence of mature cathpsin B in the conditioned medium of the more malignant cell lines coincided with a reduction in pH and an increase in the amount of cathepsin D secreted. Data from the human colorectal derived adenoma to carcinoma sequence indicate that an in vivo mechanism may exist that, dependent on the simultaneous presence of both a tumour-generated acidic extracellular environment and an elevated secretion of procathepsin D, could result in the activation of latent procathepsin outside the cell.

Adenocarcinoma↗
PubMed1995

Baboon (Papio ursinus) cathepsin L: purification, characterization and comparison with human and sheep cathepsin L.

Cathepsin L was purified from the liver of a higher primate, the baboon (Papio ursinus), largely in a single-chain form and in the form of proteolytically active complexes with an endogenous cystatin. This mimics the situation found in both human and sheep livers. Both forms of cathepsin L were active at physiological pH. Physicochemical characterization and N-terminal amino sequencing of baboon cathepsin L showed a close relationship with the human enzyme. Cystatins with characteristics similar to those found for stefins A and B could also be purified from baboon livers. Proteolytically active, SDS-stable complexes could be shown to form in vitro with the molecules characterized as stefin B, but not with stefin A type cystatins. The non-inhibitory complexes could be shown to require less cysteine for activation than free cathepsin L and this, together with the above result, might indicate that a sulfhydryl interchange mechanism is responsible for the formation of covalent, non-inhibitory complexes.

Animals↗
PubMed2000

Lysosomal cathepsin B plays an important role in antigen processing, while cathepsin D is involved in degradation of the invariant chain inovalbumin-immunized mice.

We previously reported that CA074, a specific inhibitor of cathepsin B, modulates specific immune responses from the T helper 2 (Th2) type to Th1 type in BALB/c mice infected with Leishmania major. In the present study, we found that a similar type of immune deviation was also induced in mice immunized with ovalbumin (OVA). However, treatment of mice with pepstatin A, a specific cathepsin D inhibitor, suppressed the OVA-specific proliferation of lymphocytes and blocked the development of both Th1 and Th2 cellular responses. These inhibitors did not appear to have any direct influence in vitro on functions of naive lymphocytes. OVA antigen (47 000 MW) was digested mainly into 40 000 MW protein in vitro by lysosomal proteases from naive BALB/c mice, and its digestion was markedly inhibited by the addition of CA074, but not by addition of pepstatin A, during incubation. However, pepstatin A strongly suppressed the degradation of the major histocompatibility complex class II-associated invariant chain (Ii) molecule in vivo and in vitro. Thus, cathepsin B appears to process antigens directed to preferential activation of Th2 cells, while cathepsin D may be responsible for the degradation of Ii, the processing of which is essential in initiating the antigen-specific activation of Th1 and Th2 CD4+ T cells. These lysosomal proteases may have different functions in regulating immune responses.

Animals↗
PubMed1999

Crystal structure of MHC class II-associated p41 Ii fragment bound to cathepsin L reveals the structural basis for differentiation between cathepsins L and S.

The lysosomal cysteine proteases cathepsins S and L play crucial roles in the degradation of the invariant chain during maturation of MHC class II molecules and antigen processing. The p41 form of the invariant chain includes a fragment which specifically inhibits cathepsin L but not S. The crystal structure of the p41 fragment, a homologue of the thyroglobulin type-1 domains, has been determined at 2.0 A resolution in complex with cathepsin L. The structure of the p41 fragment demonstrates a novel fold, consisting of two subdomains, each stabilized by disulfide bridges. The first subdomain is an alpha-helix-beta-strand arrangement, whereas the second subdomain has a predominantly beta-strand arrangement. The wedge shape and three-loop arrangement of the p41 fragment bound to the active site cleft of cathepsin L are reminiscent of the inhibitory edge of cystatins, thus demonstrating the first example of convergent evolution observed in cysteine protease inhibitors. However, the different fold of the p41 fragment results in additional contacts with the top of the R-domain of the enzymes, which defines the specificity-determining S2 and S1' substrate-binding sites. This enables inhibitors based on the thyroglobulin type-1 domain fold, in contrast to the rather non-selective cystatins, to exhibit specificity for their target enzymes.

Amino Acid Sequence↗
PubMed1983

Cathepsin B-like cysteine proteinase activity in sputum and immunohistologic identification of cathepsin B in alveolar macrophages.

Cathepsin B-like cysteine proteinase activity was measured, using a fluorimetric assay, in sputum samples from 27 subjects with chronic obstructive airways disease. Thirteen of the subjects had a current acute respiratory infection. Enzyme activity was detected in 11 of the 13 infected and 12 of the 14 noninfected samples. The mean cathepsin B activity observed in the infected samples was significantly greater than that of the noninfected samples. Most of the cathepsin B-like activity in sputum represented enzyme in free solution but a small proportion appeared to be complexed with alpha 2-macroglobulin. Immunohistochemical localization of cathepsin B in human lung tissue sections detected the enzyme only within macrophages.

Cathepsin B↗
PubMed1979

Cathepsin B and collagenolytic cathepsin in the aqueous humor of patients with Behçet's disease.

Cathepsin B and collagenolytic cathepsin activities were studied biochemically in human aqueous humor. The enzyme activities were found to be significantly high in the aqueous humor of the patients with Behçet's disease, but not detectable in those with senile cataract, retinoblastoma, and maxillar carcinoma. These data suggest that cathepsin B and collagenolytic cathepsin have a certain role in the inflammatory collagenolytic process of Behçet's disease.

Adult↗
PubMed1975

Improved purification of cathepsin B1 and cathepsin B2.

An improved purification of the cathepsins B1 and B2 from bovine spleen is described. In addition to the formerly used procedure, chromatography with DEAE-Sephadex or -cellulose and mercurated agarose is used. Both enzymes are obtained in an electrophoretically pure form but consist of two or more isoenzymes. The isolation procedure leads to enzymes with high specific activities in satisfactory yields. Cathepsin B1 is frequently accompanied by small amounts of an arylamidase-like enzyme that hydrolyzes leucine p-nitroanilide. However, very probably, cathepsin B1 itself has a low activity toward this substrate too. Cathepsin B2 has a comparatively high activity with its characteristic though not specific substrate, alpha-N-benzoyl-L-arginineamide, whereas the activity toward haemoglobin is far lower. Both enzymes possess an essential SH group and require EDTA and a mercaptane for full activity, but their stability is markedly impaired by storage at higher thiol concentrations; Some other properties of the enzymes are also discussed.

Animals↗
PubMed1996

Vitellogenesis-related ovary cathepsin D from Xenopus laevis: purification and properties in comparison with liver cathepsin D.

Cathepsin D was purified from ovaries of Xenopus laevis by both QAE-cellulose and pepstatin-Sepharose chromatography and then characterized and compared with Xenopus liver cathepsin D. Ovary cathepsin D appeared predominantly as a 43-kilodalton (kDa) molecular mass, as revealed by SDS-polyacrylamide gel electrophoresis, whereas the liver enzyme was obtained exclusively as a 36-kDa protein. The purified 43-kDa ovary enzyme cleaved vitellogenin limitedly to produce yolk proteins at pH 5.6. The specific activity of ovary cathepsin D was five to six times lower than that of the liver enzyme, as measured by hemoglobin-hydrolysis at pH 3, but the ovary enzyme was shown to be superior to the liver enzyme in terms of vitellogenin-cleaving activity, as examined at pH 5.6. Ovarian enzyme preparations contained variable amounts of 36-kDa species; this form was considered to be an autolytic product of the 43-kDa form arising during purification, because it was not detected in oocyte extracts but was generated by incubation of the purified 43-kDa enzyme alone in an acid solution. The conversion of the 43-kDa form by hepatic factors was accompanied by a marked increase in hemoglobin-hydrolytic activity.

Animals↗
PubMed1996

Cathepsin B in the growth of colorectal cancer: increased activity of cathepsin B in human colorectal cancer.

Cathepsin B, a thiol protease, is involved in cancer metastasis. To clarify the role of cathepsin B in tumor progression in human colorectal cancer, the relationship between its activity, immunohistochemical staining, and clinical tumor progression was investigated. Cathepsin B activity in adenocarcinomas was significantly elevated compared with that in the tumor-bearing tissue. Furthermore, the tumor/tumor-bearing tissue (T/Tb) ratio of the activity was significantly higher than that of colorectal adenoma. Immunohistochemical studies demonstrated intense staining in the cancerous tissue. With respect to the clinical stage of tumors, the activity tended to be higher in tumors that had invaded the serosa or subserosa than in those that invaded the proper muscle. The results suggest that cathepsin B participates in the progression of human colorectal cancer, and its increased expression is a sensitive marker of the differentiation between colorectal adenoma and adenocarcinoma.

Adenocarcinoma↗
PubMed1975

Studies on cathepsins of rat liver lysosomes. II. Comparative studies on multiple forms of cathepsin A.

The multiple forms of cathepsin A (AI, AII, and AIII) purified from the lysosome fraction of rat liver by Sephadex G-200 and DEAE-Sephadex chromatographies were studied comparatively. Forms AI, AII and AIII were stable between pH 3.0 and 5.5, and had pH optima for CBZ-Glu-Phe at 5.6, 5.8, and 5.9, respectively. These activities were rapidly lost on heating above 60 degrees. Their isoelectric points were at 4.7, 4.8, and 4.9, and the Michaelis constants for CBZ-Glu-Phe were calculated as 10, 6.6, and 4.2 X 10(-4)M, respectively. Activity was inhibited by Ag+, Au3+, Hg2+, iodine, and p-chloromercuribenzoate (PCMB). Diisopropyl fluorophosphate (DFP), phenylmethanesulfonyl fluoride (PMSF), toluenesuffonyl fluoride (TSF), and sodium dodecyl sulfate (SDS) were inhibitory at a concentration of 10(-3)M. Soybean trypsin inhibitor, pepstatin, leupeptins, and antipain were not inhibitory, while chymostatin caused slight inhibition. No distinct difference was observed in the effects of these compounds on the multiple forms of cathepsin A despite differences in the molecular weights of these forms (100,000, 200,000, and 420,000, respectively). In immuno-diffusion analysis, cathepsin AI, AII, and AIII which had been treated with EDTA, dithiothreitol, PCMB, and a high concentration of NaCl, gave the same precipitin patterns as the untreated enzymes, but treatment with 6 M urea caused a slight alteration of the pattern. After SDS-treatment (50 mM or more), the precipitin lines of these multiple forms fused and gave a single, identical line. This suggests that the different forms of the cathepsin A are all composed of subunits which are immunologically identical or closely related, and that the subunits are mainly bound by hydrophobic forces. This conclusion is supported by results obtained by poliacrylamide gel electrophoresis in the presence of SDS.

Animals↗
PubMed1996

Structural requirements for cathepsin B and cathepsin H inhibition by kininogens.

Domain 3 (D3) of human kininogens, the major cysteine proteinase inhibitors in plasma, has been shown to be the tightest binding inhibitory domain for cathepsins B and H. D3 was expressed in three fragments as its exon products as follows: exon 7 (Gly235-Gln292), exon 8 (Gln292-Gly328), and exon 9 (Gln329-Met357). Exon products 7, 8, and 9 alone as well as exon product 7 + 9 each exhibited an 1C50 value 5- to 30-fold higher (5-30 microM) than exon products 7 + 8 and 8 + 9 (0.9-1.3 microM) for cathepsins B and H, respectively. However, in turn, the exon products 7 + 8 and 8 + 9 seemed to be less potent inhibitors than the intact D3 (10, 200 nM) or HK (200, 500 nM) molecule. These results clearly indicate that an intact molecule of HK or its domain 3 as a whole is required for optimal inhibition of cathepsins B and H.

Amino Acid Sequence↗
PubMed1986

Elevations of cathepsin B and cathepsin L activities in forelimb and hind limb muscles of genetically dystrophic mice.

The combined activities of cathepsin B and cathepsin L were studied in the forelimb and hind limb muscles of dystrophic mice. The activities of these proteases in the forelimb and hind limb muscles of young and adult dystrophic mice were significantly higher than those in normal mice. However, clinical involvement of dystrophy appeared in the hind limbs but not in the forelimbs. We therefore suggest that the increase in protease activity begins at a very early age and that the clinical involvement is not linked with the increase in cathepsin B and L.

Animals↗
PubMed2002

Comparison of potential biological markers cathepsin B, cathepsin L, stefin A and stefin B with urokinase and plasminogen activator inhibitor-1 and clinicopathological data of breast carcinoma patients.

Cysteine, serine and metalloproteinases and their respective inhibitors are involved in tumor cell invasion and may have prognostic value for the outcome of malignant disease. The aim of the study was to compare the expression of new potential biological tumor markers, the lysosomal cysteine proteinases and their endogenous inhibitors, with that of the serine proteinases and their inhibitors in breast cancinoma and to relate their levels to the clinicopathological factors of the disease. Enzyme-linked immunosorbent assays (ELISAs) were used to measure cysteine cathepsin B (CatB) and cathepsin L (CatL) and their inhibitors, stefin A (StA) and stefin B (StB), together with urokinase (u-PA) and plasminogen activator inhibitor-1 (PAI-1), in 150 cytosols of primary invasive breast carcinoma. A good correlation was found between the levels of the two cysteine proteinases but only a moderate one between those of the cysteine and serine proteinases. u-PA and PAI-1 levels correlated positively with histological grade and negatively with estrogen receptor (ER) status. PAI-1 correlated with most clinicopathological factors that indicate the progression of the disease, while cathepsins and stefins were independent of these factors. In the total group of patients, high u-PA and PAI-1 and low StB levels correlated significantly with shorter disease-free survival (DFS), while CatB, CatL and StA did not. In lymph node negative patients, high CatB and CatL were also associated with shorter DFS, while u-PA remained the most significant of all these biological markers. In conclusion, this retrospective study showed u-PA to be of better prognostic relevance than the cysteine proteinases, though CatB and CatL were relevant for prognosis in lymph node negative breast cancer patients.

Adult↗
PubMed2004

Cathepsin L is involved in cathepsin D processing and regulation of apoptosis in A549 human lung epithelial cells.

Cathepsins are implicated in a multitude of physiological and pathophysiological processes. The aim of the present study was to investigate the function of cathepsin L (catL) in the proteolytic network of human lung epithelial cells and its role in the regulation of apoptosis. We found that catL-deficient A549 cells as well as lung tissue extracts of catL(-/-) mice express increased amounts of single-chain cathepsin D (catD). Degradation experiments indicate that catL specifically degrades the single-chain isoform of catD. Furthermore, we found that catL-deficient cells showed increased sensitivity to apoptosis. Finally, we demonstrate that the inhibition of catD activity by pepstatin A decreased the number of apoptotic cells in catL-deficient A549 cells after anti-Fas treatment. In conclusion, catL is involved in catD processing and the accumulation of catD isoforms in catL-deficient cells is associated with increased rates of spontaneous and anti-Fas-induced apoptosis.

Animals↗
PubMed2000

Distinct roles of cathepsin K and cathepsin L in osteoclastic bone resorption.

The role of cathepsin K (CAK), cloned as a novel collagenolytic cysteine protease (CCP), cathepsin L (CAL) and cathepsin B (CAB) in bone resorption was investigated. In mouse calvarial organ culture medium, CAL, detected in trace amounts in control conditions, and CCP activity were increased by stimulants of bone resorption: 1alpha,25-(OH)2D3 parathyroid hormone (PTH), IL-1alpha, IL-6 or TNF-alpha. CAK was the most abundantly detected CCP and was not increased by these stimulants. In the absence of the stimulants, only antisense oligodeoxynucleotide (AS-ODN) for CAK suppressed collagenolysis and CCP activity. On the other hand, in the presence of the stimulants, AS-ODN for both CAK and CAL suppressed collagenolysis and CCP activity, and these activities were additive. AS-ODN for CAB did not suppress collagenolysis. These results suggested CAK was constitutively synthesized as the main CCP, and CAL was synthesized as an inducible CCP in osteoclasts to degrade type-I collagen in combination with CAK.

Animals↗