Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01034 (cystatin C)
 3,397 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cysteine proteinase inhibitors (CpI) of all three families were found in ascites fluid from patients with ovarian carcinoma. CPIs were isolated by affinity chromatography on carboxymethylated papain Sepharose, followed by gel filtration, anti-stefin-Sepharose and ion exchange chromatography. The highest apparent inhibition against cathepsin B (Cat B) was found in the low molecular mass (LMM) CPI fraction. Immunochemical analysis of this fraction revealed the presence of cystatin C and both stefins A and B while the high molecular mass (HMM) CPI fraction contained kininogens. We demonstrated that CPIs were not completely associated with cysteine proteinases (CPs): about 20% of HMM CPIs and 50% of LMM CPIs were free in native ascites fluid. Affinity chromatography on anti-Cat B-Sepharose revealed that the major LMM CPI, associated with Cat B in native ascites fluid, was the full length form of cystatin C, pI 9.3, and not its truncated form, pI 7.85. The latter was isolated and found to inhibit Cat B in vitro with apparent Ki 0.18 +/- 0.2 nM. Stefin A was isolated from alkaline activated ascites fluid in its two isoforms, pI 4.6 and 4.9. In native ascites, the pI 4.9 isoform was mostly associated with Cat B. Ki for Cat B was 3.55 +/- 1.7 nM, not significantly different from the Ki values measured for stefin A, isolated from other human tissues and biological fluids.
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PMID:Cystatins and stefins in ascites fluid from ovarian carcinoma. 173 49

Cystatin C, a cysteine proteinase inhibitor has recently been suggested to be a potent regulator of inflammatory processes and may act in defense against viral and bacterial infections. Two common forms of the protein were purified from the urine of a patient having received a renal transplant. The slow form of cystatin C possessed the N-terminal tetrapeptide Lys Pro Pro Arg, which was cleaved in the fast form. This peptide sequence, called postin, was synthesized. The three molecules, slow and fast forms of cystatin and the synthetic peptide, were tested for their effects on the migration activity of human polymorphonuclear neutrophils (PMNs). The slow form was found to display both chemotactic and chemokinetic activities, while the fast form and postin were only chemokinetic. Nevertheless, all the substances could induce a "motile" morphology. In addition, the two forms of cystatin C were powerful inhibitors of PMN chemotaxis induced by complement-derived chemotactic factors. This suggests that cystatin C in its two different cleaved forms and the N-terminal tetrapeptide can modulate PMN locomotion. Cysteine proteases may therefore play a role in neutrophil migration activity.
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PMID:Neutrophil chemotactic activity is modulated by human cystatin C, an inhibitor of cysteine proteases. 236 32

Cysteine proteinases are important not only in the intracellular catabolism of peptides and proteins and in the processing of prohormones and proenzymes, but also in the penetration of normal human tissue by malignant cells and possibly microorganisms, including viruses. Cystatin C is a human cysteine proteinase inhibitor present in extracellular fluids. We have synthesized peptide derivatives mimicking the proposed proteinase-binding centre of cystatin C and find that they irreversibly inhibit cysteine proteinases. Several bacteria produce proteinases, so we tested a tripeptide derivative (Z-LVG-CHN2) for in vitro anti-bacterial activity against a large number of bacterial strains belonging to thirteen different species. It was found to inhibit specifically the growth of all strains of group A streptococci. The susceptibility of these human pathogens to the peptide was compared with that to well-established anti-streptococcal antibiotics such as tetracycline and bacitracin. Moreover, the peptide was active in vivo against group A streptococci: mice injected with lethal doses of these bacteria were cured by a single injection of Z-LVG-CHN2. The cysteine proteinase produced by group A streptococci was isolated and found to be inhibited by Z-LVG-CHN2; moreover, excess proteinase relieved the growth inhibition caused by the peptide derivative, suggesting that the antibacterial activity of Z-LVG-CHN2 is due to inhibition of this cysteine proteinase. This strategy of blocking proteinases with peptide derivatives that mimic naturally occurring inhibitors could be useful in the construction of new agents against other microorganisms, including viruses.
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PMID:Bacterial growth blocked by a synthetic peptide based on the structure of a human proteinase inhibitor. 264 59

Cysteine proteases of the papain family generally exhibit broad P1 specificity. A notable exception is papaya proteinase IV (PPIV), which only accepts Gly at this position. In all other cysteine proteases the S1 subsite residues 23 and 65 (papain numbering) are absolutely conserved as Gly, while in PPIV they are replaced by Glu and Arg, respectively. These differences appear to underlie both PPIV specificity and its resistance to inhibition by cystatins. To test this hypothesis, the equivalent residues (Gly27 and Gly73) in the mammalian cysteine protease cathepsin B were changed to Glu and Arg, respectively. Relative to the wild-type enzyme, the Gly27Glu and Gly73Arg mutants showed a drastic reduction in activity with substrates containing a P1 Arg. In contrast, substrates having a Gly residue in P1 were hydrolyzed effectively. The double mutant (Gly27Glu:Gly73Arg) exhibited no detectable activity against any substrate studied. Inhibition of the Gly73Arg mutant by E-64 [1-(L-trans-epoxysuccinyl-L-leucylamino)-4-guanidinobutane] was found to be similar to that of the wild-type enzyme. In contrast, inhibition by cystatin C exhibited a 20,000-fold reduction. These results demonstrate the dramatic influence of side chains at sequence locations 27 and 73 on the S1 subsite specificity of cysteine proteases.
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PMID:Modification of S1 subsite specificity in the cysteine protease cathepsin B. 777 Apr 53

Cysteine proteinase inhibitors of the cystatin superfamily have been identified in many living organisms. However, knowledge of the tissue distribution of such inhibitors is limited. To elucidate this distribution in mammals, we have investigated the expression of the gene for cystatin C, belonging to cystatin family II, in several bovine tissues. In situ hybridisation with a digoxigenin-labelled cRNA probe demonstrated a high concentration of bovine cystatin C mRNA in the secretory epithelial cells of the choroid plexus, and also intense staining in cells of lymphoid tissue and in Sertoli cells. Cystatin C mRNA was also present in scattered neurons and glial cells throughout the cerebrum and the cerebellum. In the submandibular gland, specific mRNA was found mainly in striated intralobular ducts and interlobular ducts. The expression of cystatin C in brain tissue is of particular interest, as the inhibitor appears to be involved in certain neurological diseases. The main production of cystatin C within the brain is believed to be by astrocytes. However, this work shows that also neurons from young, normal individuals express cystatin C.
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PMID:Tissue distribution of bovine cystatin C analysed by in situ hybridisation. 1096 65

Cysteine-proteinases (CP) of the papain family can be affinity-adsorbed by egg white cystatin C coupled to Sepharose 4B, thus allowing their selective isolation from either tissue or cultured cell extracts as well as biolological fluids and culture media. CP complexed by immobilized cystatin are further analyzed by means of SDS-PAGE and Western blot followed by serial or parallel immunological detection. The single-step affinity adsorption of papain-like enzymes has the advantage, over immunoprecipitation techniques, of yielding the simultaneous and comprehensive picture of most CP, as both precursor and mature forms, in a given sample. Moreover, cell extraction in the presence of immobilized cystatin ensures a fast complexation of CP, avoiding artifacts, due to conversion, degradation, and, eventually, subtraction of constitutive enzymes from the sample because of their interactions with endogenous inhibitors. This will provide a pattern that might reflect more closely the real CP levels in intact cells. The method may be useful in the field of biochemistry, cell biology, and, possibly, clinical chemistry to perform rapid analyses of papain-like enzymes and to monitor changes in both cellular and extracellular CP profiles along with different physiopathological conditions.
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PMID:A cystatin-based affinity procedure for the isolation and analysis of papain-like cysteine proteinases from tissue extracts. 1116 16

Cysteine protease-inhibiting proteins of the cystatin superfamily can inhibit the replication of certain viruses and bacteria. The inhibitory centre of human cystatin C, the most widely distributed human cystatin, comprises three peptide segments. The present work describes the synthesis and antibacterial activity of 27 new peptidyl derivatives or cyclopeptides based upon the aminoterminal segment Arg8-Leu9-Val10-Gly11. Fourteen of the new compounds displayed antibacterial activity against from 1 up to 9 of 17 clinically important bacterial species tested. Antiproteolytic activity of a compound was usually not required for its antibacterial capacity. Peptidyl diazomethanes generally had a very narrow antibacterial spectrum, inhibiting only Streptococcus pyogenes, whereas cyclopeptides and peptidyl derivatives of the general structure X-Arg-Leu-NH-CH(iPr)-CH2-NH-Y had a much wider spectrum. The most potent of these substances displayed approximately equal minimal inhibitory and bactericidal concentrations of about 20 microg/ml for both Staphylococcus aureus and S. pyogenes and were devoid of antiproteolytic activity. Several of the new substances could protect mice against lethal intraperitoneal challenge with S. pyogenes. Though their target remains to be disclosed, the group of substances here reported might be promising for the development of antibacterial drugs and the discovery of novel principles of action.
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PMID:Synthesis and antibacterial properties of peptidyl derivatives and cyclopeptides structurally based upon the inhibitory centre of human cystatin C. Dissociation of antiproteolytic and antibacterial effects. 1116 42

Cysteine proteases are proteolytic enzymes involved in many pathological processes and found in the lysosomes of cells; examples include the cathepsins B, H and L. The role of cysteine proteases is crucial in normal cellular metabolism, being fundamental to intracellular protein turnover, degradation of collagen, and cleaving of precursor proteins. Cysteine protease inhibitors, of which the cystatin superfamily are one example, constitute the final regulatory step in the control of cysteine proteases. Currently, cystatin C is the most frequently investigated family member and is involved in processes such as tumour invasion and metastasis, inflammatory processes and some neurological diseases. In such diseases the emphasis is placed on the fine balance and regulation of both the cysteine proteases and their inhibitors, with an imbalance resulting in a pathological state. In addition, the constant serum concentration of cystatin C means it has possible application as a replacement for creatinine in the measurement of glomerular filtration rate. To date, several assays have been developed and studies show a promising future for its use in the medical laboratory, and not just as a research tool. This review of cystatin C includes a brief history of its discovery and characterisation, provides a guide to some of the processes in which its role is fundamental, and highlights developments in its use as a clinical biomarker in the disease processes discussed.
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PMID:Diagnostic applications of cystatin C. 1120 65

BACKGROUND: Tumor metastasis is a frequent cause of treatment failure for cancer patients. A key feature of metastatic cancer cells is their invasive ability. Cysteine proteases contribute to invasive properties of many cancer cell types. To analyze the contribution of cysteine proteases to metastasis we have over-expressed in B16 melanoma cells the natural cysteine protease inhibitor, cystatin C. We measured in vitro invasion of cystatin over-expression clones with Boyden chamber type assays. Tail-vein injections of cells were used to compare lung tumor colonization. Subcutaneous tumor growth and tumor cell metastasis from primary tumors were also analyzed. Apoptosis of tumor cells was measured in lung tissues following melanoma cell injection. RESULTS: Results show the in vitro invasion of cystatin C over-expressing cells was dramatically inhibited. Lung tumor colonization was also reduced. Increased tumor cell apoptosis was found to be an important factor and may be related to the reduced tumor burden noted in this system of melanoma metastasis. CONCLUSION: Cysteine proteases therefore, may be a target for future anti-metastatic therapies.
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PMID:Late stage inhibition of hematogenous melanoma metastasis by cystatin C over-expression. 1590 19

Cysteine proteinases, especially cathepsin K, play an important role in osteoclastic degradation of bone matrix proteins and the process can, consequently, be significantly inhibited by cysteine proteinase inhibitors. We have recently reported that cystatin C and other cysteine proteinase inhibitors also reduce osteoclast formation. However, it is not known which cysteine proteinase(s) are involved in osteoclast differentiation. In the present study, we compared the relative potencies of cystatins C and D as inhibitors of bone resorption in cultured mouse calvariae, osteoclastogenesis in mouse bone marrow cultures, and cathepsin K activity. Inhibition of cathepsin K activity was assessed by determining equilibrium constants for inhibitor complexes in fluorogenic substrate assays. The data demonstrate that whereas human cystatins C and D are equipotent as inhibitors of bone resorption, cystatin D is 10-fold less potent as an inhibitor of osteoclastogenesis and 200-fold less potent as an inhibitor of cathepsin K activity. A recombinant human cystatin C variant with Gly substitutions for residues Arg8, Leu9, Val10, and Trp106 did not inhibit bone resorption, had 1,000-fold decreased inhibitory effect on cathepsin K activity compared to wildtype cystatin C, but was equipotent with wildtype cystatin C as an inhibitor of osteoclastogenesis. It is concluded that (i) different cysteine proteinases are likely to be involved in bone resorption and osteoclast formation, (ii) cathepsin K may not be an exclusive target enzyme in any of the two systems, and (iii) the enzyme(s) involved in osteoclastogenesis might not be a typical papain-like cysteine proteinase.
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PMID:Different cysteine proteinases involved in bone resorption and osteoclast formation. 1590 14


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