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)

Papain was labelled by attachment of the fluorescent groups 2-(4'-acetamidoanilino)naphthalene-6-sulphonic acid (AANS) or N-(acetylaminoethyl)-8-naphthylamine-1-sulphonic acid (AEDANS) to the active-site cysteine residue, with the aim of using the labelled papains as probes in competitive titrations of unlabelled cysteine proteinases with their inhibitors. The interaction between the labelled papains and cystatins was accompanied by an increase in fluorescence emission of up to 38-fold for AANS-papain and approximately 3.5-fold for AEDANS-papain. Fluorescence titrations gave dissociation equilibrium constants of 3.1 and 0.6 microM for the binding of chicken cystatin and recombinant human cystatin C respectively to AANS-papain and of 11.9 microM for the binding of chicken cystatin to AEDANS-papain. The kinetics of interaction of chicken cystatin with AANS-papain showed an unusual biphasic dependence of the observed pseudo-first-order rate constant on inhibitor concentration, consistent with the reaction occurring via both pathways of a general two-step binding mechanism. AANS-papain was selected as the most suitable probe for competitive titrations of unlabelled active or inactivated cysteine proteinases with inhibitors. This technique, which provides stoichiometries and dissociation constants for the interaction between unlabelled enzyme and inhibitor, allows monitoring of the interactions by a large fluorescent signal in a wavelength region where the interacting proteins do not contribute to the observed fluorescence. Such competitive titrations of active papain or actinidin with chicken cystatin or recombinant human cystatin C all gave inhibitor/enzyme stoichiometries of close to 1.0. A dissociation constant of 1.8 microM for the reaction of chicken cystatin with a papain derivative, S-[N-(3-carboxypropyl)succinimidyl]-papain, was also determined by the same technique. These results show the usefulness of the fluorescent papains for the characterization of interactions between cysteine-proteinase inhibitors and their target enzymes.
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PMID:Papain labelled with fluorescent thiol-specific reagents as a probe for characterization of interactions between cysteine proteinases and their protein inhibitors by competitive titrations. 204 69

We have examined the amino acid sequences of a number of proteins that have been suggested to be related to chicken cystatin, a protein from chicken egg white that inhibits cysteine proteinases. On the basis of statistical analysis, the following proteins were found to be members of the cystatin superfamily: human cystatin A, rat cystatin A(alpha), human cystatin B, rat cystatin B(beta), rice cystatin, human cystatin C, ox colostrum cystatin, human cystatin S, human cystatin SA, human cystatin SN, chicken cystatin, puff adder cystatin, human kininogen, ox kininogen, rat kininogen, rat T-kininogens 1 and 2, human alpha 2HS-glycoprotein, and human histidine-rich glycoprotein. Fibronectin is shown not to be a member of this superfamily, and the c-Ha-ras oncogene protein p21 (Val-12) probably is not a member also. It was convenient to divide members of the superfamily into four types on the basis of the presence of one, two, or three copies of cystatin-like segments and the presence or absence of disulfide bonds. Evolutionary dendrograms were calculated by three methods, and from these we have constructed a scheme depicting the sequence of events in the evolution of these proteins. We suggest that about 1000 million years ago a precursor containing disulfide loops appeared, and that all disulfide-containing cystatins are derived from this. We follow the evolution of the proteins of the superfamily along four main lineages, with special attention to the part that duplication of segments has played in the development of the more complex molecules.
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PMID:Evolution of proteins of the cystatin superfamily. 210 24

Two isoelectric forms of human cystatin C with pI 9.2 and 7.8 have been isolated from urine of patients with different nephrological disorders. Treatment of both forms with alkaline phosphatase revealed that the difference between them is not due to the phosphorylation of some amino-acid residue. Further purification of cystatin C with pI 9.2 by hydrophobic chromatography and N-terminal sequencing showed that it consists predominantly of the full-length form of cystatin C with the N-terminal sequence SSPG-. Cystatin C with pI 7.8 was separated into two peaks. The first represented a pure form truncated by an octapeptide and beginning with the N-terminal sequence LVGG-. The second was a mixture containing 33% of the first peak and 66% of a truncated form with the N-terminal sequence VGGP-. Inhibitory activity of the full-length cystatin C and the pure truncated form has been measured against cathepsins B, H and L and show no significant differences in Ki values. These results further support the proposed mechanism of interaction of cysteine proteinases with their inhibitors cystatins (Bode, W., Engh, R., Musil, D., Thiele, U., Huber, R., Karshikow, A., Brzin, J., Kos, J. & Turk, V. (1988) EMBO J. 7, 2593-2599).
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PMID:Different forms of human cystatin C. 222 56

Hydropathic anticomplementarity of amino acids indicates that peptides derived from complementary DNA strands may form amphiphilic structures and bind one another. By using this concept, we have found that the antisense peptide Ser-Tyr-Asp-Leu complementary to the segment Gln-Ile-Val-Ala-Gly (residues 55-59) in cystatin C (an inhibitor of cysteine proteases) is located at positions 611-614 of the beta chain of human C4, the fourth component of complement. Here we describe and characterize the specific interaction between cystatin C and C4 by ligand affinity chromatography and ELISA. Interaction between the two native proteins was mimicked on replacement of one of them with the corresponding sense-antisense peptide coupled to a carrier protein, and the binding was inhibited by these synthetic peptides in solution. Through the interaction with C4, cystatin C may play a regulatory role in complement activation that might be of particular importance at tissue sites where both proteins are produced by macrophages.
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PMID:Binding of cystatin C to C4: the importance of sense-antisense peptides in their interaction. 230 99

The major inhibitor of the cysteine class of proteinases found in human body fluids, such as spinal fluid, milk, and seminal plasma, is cystatin C. In this study we show that human bronchoalveolar fluid also contains cystatin C and examine cystatin C expression by alveolar macrophages in vitro. Immunoprecipitation of extracts of metabolically labeled cells and immunoblotting of cellular extracts and culture media show that cystatin C is synthesized as a 14 (+/- 0.5) kilodalton (kD) protein and that greater than 90% of the protein is released as the 14 kD product into the culture supernatant (26.5 +/- 6.8 ng per 10(6) cells per 24 h). Cystatin C is not one of the most abundant proteins secreted during the first 24 h in vitro, representing approximately 10 to 12% of the total protein released by normal nonsmoker macrophages. Alveolar macrophages obtained from cigarette smokers or nonsmoker macrophages exposed to zymosan in vitro released 10 to 55% less cystatin C than nonsmoker macrophages. We also assayed culture supernatants from macrophages of smokers and nonsmokers for functional cystatin C. Supernatants of nonsmoker macrophages inhibited cathepsin B-like amidolytic activity in a fluorometric assay at pH 5.5. The inhibition was blocked by adsorption with Sepharose-coupled cystatin C antibodies and the inhibitor subsequently recovered from the Sepharose beads. In contrast, supernatants from smoker macrophages had obvious cathepsin B-like activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Identification of cystatin C, a cysteine proteinase inhibitor, as a major secretory product of human alveolar macrophages in vitro. 231 99

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

Peptides spanning the entire, or part of, the Gly4-Glu21 segment of the human cysteine proteinase inhibitor cystatin C have been synthesized. Peptides containing residues on the N-terminal side of Gly11 were rapidly cleaved by papain at the bond Gly11-Gly12 whereas a peptide starting at residue Gly11 was not, thus demonstrating 1. that the N-terminal segment of cystatin C has an amino acid sequence that would allow rapid interaction between this segment and the substrate pocket of papain and, if this interaction takes place, that 2. the cystatin C residue Gly11 would be in the P1 position, and 3. the major interaction would be between residues Arg8-Val10 and the papain substrate pocket subsites S4, S3 and S2, respectively. Several modified peptide derivatives containing either diazomethane groups or peptide bond isosters were synthesized based on the structure of the Leu9-Gly11 segment of cystatin C and tested for their cysteine proteinase inhibiting capacity. The peptidyl derivatives, t-butyloxycarbonyl-valyl-glycyl-diazomethane and benzyloxycarbonyl-leucyl-valyl-glycyl-diazomethane irreversible inhibited the cysteine proteinases papain, bovine cathepsin B and streptococcal proteinase, but did not influence the activity of serine, aspartic or metallo-proteinases.
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PMID:Synthesis of cysteine proteinase inhibitors structurally based on the proteinase interacting N-terminal region of human cystatin C. 240 May 74

Cystatin C, a protein inhibitor of lysosomal cysteine proteinases, was demonstrated by immunohistochemical techniques to be present in the birefringent amyloid deposits of the small arteries in the cerebrum, cerebellum, and leptomeninges of 10 Icelandic individuals with hereditary cerebral hemorrhage with amyloidosis. Specimens from other organs were investigated in one of the patients, and amyloid angiopathy characterized by an immunoreactivity of cystatin C was found in a submandibular lymph node. No immunoreactivity of amyloid fibril protein AA, kappa or lambda immunoglobulin light chain, or prealbumin was observed. Significantly low cerebrospinal fluid concentrations of cystatin C were found in all 9 investigated individuals with hereditary cerebral hemorrhage with amyloidosis. The concentrations of beta 2-microglobulin, albumin, and IgG in the cerebrospinal fluid were within normal limits. Isoelectric focusing showed that cystatin C from the cerebrospinal fluid of 9 patients with hereditary cerebral hemorrhage with amyloidosis had an isoelectric point identical to that of normal individuals. This investigation demonstrates that hereditary cerebral hemorrhage with amyloidosis may be diagnosed by two laboratory methods: immunohistochemical investigation of cystatin C in brain tissue specimens and quantitation of cystatin C in cerebrospinal fluid.
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PMID:Immunohistochemical characterization of the amyloid deposits and quantitation of pertinent cerebrospinal fluid proteins in hereditary cerebral hemorrhage with amyloidosis. 243 60

Cystatin C is an inhibitor of lysosomal cysteine proteases and consists of 120 amino acids. A variant of cystatin C lacking the first NH2-terminal residues and having one amino acid substitution at position 68 forms amyloid deposits mainly in the walls of brain arteries, causing fatal strokes in Icelandic patients with familial cerebral hemorrhage secondary to a form of an autosomal dominant amyloidosis. To understand the molecular basis of the genetic defect, the gene encoding cystatin C was isolated from genomic DNA libraries made from normal tissue and the brain of an Icelandic patient with hereditary cerebral hemorrhage with amyloidosis (HCHWA-I). The data indicate that the cystatin C gene encodes a polypeptide of 146 amino acids, of which the first 26 correspond to a secretory peptide signal sequence. The gene contains two intervening sequences that interrupt the coding region at amino acids 55 and 93. Comparison with genes encoding salivary cystatins and kininogen proteins show sequence homology and conservation of exon-intron structure. Except for a mutation in the second exon (CAG instead of CTG in the normal gene, resulting in the substitution of glutamine for a leucine residue), the gene cloned from the brain of the Icelandic patient is identical to the normal cystatin C gene. Thus, HCHWA-I is the first familial type of amyloidosis related to a point mutation in a gene encoding for an inhibitor. The mutation in the structural gene encoding cystatin C appears to be the primary defect in this inherited disorder causing amyloid fibril formation and accumulation followed by cerebral hemorrhage.
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PMID:Stroke in Icelandic patients with hereditary amyloid angiopathy is related to a mutation in the cystatin C gene, an inhibitor of cysteine proteases. 254 Dec 23

Hereditary cystatin C amyloid angiopathy (HCCAA) is an autosomal dominant disorder leading to massive brain hemorrhage and death in young adults (Jensson et al., 1987). A variant of a potent inhibitor of cysteine proteinases, cystatin C (Barrett et al., 1984), is deposited as amyloid fibrils in the cerebral arteries of the patients (Ghiso et al., 1986). We have used the full length cystatin C cDNA probe (Abrahamson et al., 1987) to demonstrate a mutation in the codon for leucine at position 68, which abolishes an Alu I restriction site in cystatin C gene of the HCCAA patients. The Alu I marker has been used to show that this mutation is transmitted only in the affected members in all eight families investigated, proving that the mutated cystatin C gene causes HCCAA. This DNA marker will be useful for the diagnosis of HCCAA in patients, asymptomatic affected individuals and also for pre-natal diagnosis. HCCAA is the first human disorder known to be caused by an abnormal gene for a cysteine proteinase inhibitor.
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PMID:Mutation in the cystatin C gene causes hereditary brain hemorrhage. 260 20


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