Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.22.36 (caspase-1)
 6,285 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Protease A is 870-fold purified by means of isoelectric precipitation, DEAE-cellulose chromatography and gel filtration through Sephadex G-50, the yield of the enzyme being 28%. The purified preparation is free of contaminant proteolytic activity and is almost homogenous chromatographically, but it produces a complex pattern under electrophoresis in 30% polyacrylamide gel, which is probably due to enzyme autolysis. As evidenced from the effect of protease A on A and B chains of insulin, the enzyme has a wide substrate specificity. It hydrolyses native vetch legumin and vicilin up to peptides having on average 9 and 16 amino acid residues respectively. No free amino acids were found in hydrolysates of both vetch proteins. Thus, protease A is an endopeptidase, which probably plays the main role in the process of reserve proteins degradation.
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PMID:[Partial purification and characterization of protease A of germinating vetch seeds, hydrolyzing native reserve proteins]. 58 33

Three major esteroproteases, proteases A and D and P-esterase, obtained from the glands were studied kinetically and chemically; two (proteases A and D) were identified. Protease A is composed of a single subunit, molecular weight (27,600) similar to the native molecule (27,000); protease D consists of three subunits, approximate molecular weights of 9200, 7600 and 4600. P-esterase contains two subunits, approximate molecular weights of 7100 and 14,000. Protease A exhibits a strong kinin-releasing activity; the other two enzymes have low activity. Protease D binds to low molecular weight-epidermal growth factor, forming a complex which has an electrophoretic mobility similar to that of high molecular weight-epidermal growth factors. When beta-nerve growth factor was incubated with protease A, the amino-terminal amino acid, serine, was lost from the growth factor and a new amino-terminal amino acid, methionine, appeared. These data indicate that proteases D and A are the same proteins as epidermal growth factor-binding protein and beta-nerve growth factor endopeptidase, respectively. From a comparison of the peptide maps of trypsin-digests of the enzymes, the proteases A and D were inferred to have a similar primary structure.
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PMID:Characterization of two esteroproteases from the male mouse submandibular gland. 630 36

Metacaspases in plants, fungi, and protozoa constitute new members of a conserved superfamily of caspase-related proteases. A yeast caspase-1 protein (Yca1p), which is the single metacaspase in Saccharomyces cerevisiae, was shown to mediate apoptosis triggered by oxidative stress or aging in yeast. To examine whether plant metacaspase genes are functionally related to YCA1, we carried out analyses of AtMCP1b and AtMCP2b, representing the two subtypes of the Arabidopsis metacaspase family, utilizing yeast strains with wild-type and the disrupted YCA1 gene (yca1Delta). Inducible expression of AtMCP1b and AtMCP2b significantly promoted yeast apoptosis-like cell death of both the wild-type and yca1Delta strains, relative to the vector controls, during oxidative stress and early aging process. Mutational analysis of the two AtMCPs revealed that their cell-death-inducing activities depend on their catalytic center cysteine residues as well as caspase-like processing. In addition, the phenotype induced by the expression of two AtMCPs was effectively prevented when the cells were pretreated with a broad-spectrum caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl-ketone. These results suggest that the two subtypes of Arabidopsis metacaspases are functionally related to Yca1p with caspase-like characteristics. However, we found that bacterial and yeast extracts containing AtMCP1b, AtMCP2b, or Yca1p exhibit arginine/lysine-specific endopeptidase activities but cannot cleave caspase-specific substrates. Together, the results strongly implicate that expression of metacaspases could result in the activation of downstream protease(s) with caspase-like activities that are required to mediate cell death activation via oxidative stress in yeast. Metacaspases from higher plants may serve similar functions.
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PMID:Two Arabidopsis metacaspases AtMCP1b and AtMCP2b are arginine/lysine-specific cysteine proteases and activate apoptosis-like cell death in yeast. 1569 45

Caspase-1 is a key endopeptidase responsible for the post-translational processing of the IL-1beta and IL-18 cytokines and small-molecule inhibitors that modulate the activity of this enzyme are predicted to be important therapeutic treatments for many inflammatory diseases. A fragment-assembly approach, accompanied by structural analysis, was employed to generate caspase-1 inhibitors. With the aid of Tethering with extenders (small molecules that bind to the active-site cysteine and contain a free thiol), two novel fragments that bound to the active site and made a disulfide bond with the extender were identified by mass spectrometry. Direct linking of each fragment to the extender generated submicromolar reversible inhibitors that significantly reduced secretion of IL-1beta but not IL-6 from human peripheral blood mononuclear cells. Thus, Tethering with extenders facilitated rapid identification and synthesis of caspase-1 inhibitors with cell-based activity and subsequent structural analyses provided insights into the enzyme's ability to accommodate different inhibitor-binding modes in the active site.
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PMID:Structural analysis of caspase-1 inhibitors derived from Tethering. 1651 Oct 67

Programmed cell death (PCD) is crucial for cellular growth and development in multicellular organisms. Although distinct PCD features have been described for unicellular eukaryotes, homology searches have failed to reveal clear PCD-related orthologues among these organisms. Our previous studies revealed that a surface-reactive monoclonal antibody (mAb) 1D5 could induce multiple PCD pathways in the protozoan Blastocystis. In this study, we identified, by two-dimensional gel electrophoresis and mass spectrometry, the target of mAb 1D5 as a surface-localized legumain, an asparagine endopeptidase that is usually found in lysosomal/acidic compartments of other organisms. Recombinant Blastocystis legumain displayed biphasic pH optima in substrate assays, with peaks at pH 4 and 7.5. Activity of Blastocystis legumain was greatly inhibited by the legumain-specific inhibitor carbobenzyloxy-Ala-Ala-AAsn-epoxycarboxylate ethyl ester (APE-RR) (where AAsn is aza-asparagine) and moderately inhibited by mAb 1D5, cystatin, and caspase-1 inhibitor. Interestingly, inhibition of legumain activity induced PCD in Blastocystis, observed by increased externalization of phosphatidylserine residues and in situ DNA fragmentation. In contrast to plants, in which legumains have been shown to play a pro-death role, legumain appears to display a pro-survival role in Blastocystis.
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PMID:Blastocystis legumain is localized on the cell surface, and specific inhibition of its activity implicates a pro-survival role for the enzyme. 1991 7

Endopeptidases catalyze the internal cleavage of proteins, playing pivotal roles in protein turnover, substrate maturation, and the activation of signaling cascades. A broad range of biological functions in health and disease are controlled by proteases, yet assays to characterize their activities at a proteomic scale do not exist. To address this unmet need, we developed Sensing EndoPeptidase Activity via Release and recapture using flAnking Tag Epitopes (SEPARATE), which uses a monovalent phage display of the human proteome at a 90-aa peptide resolution. We demonstrate that SEPARATE is compatible with several human proteases from distinct catalytic classes, including caspase-1, ADAM17, and thrombin. Both well-characterized and newly identified substrates of these enzymes were detected in the assay. SEPARATE was used to discover a non-canonical caspase-1 substrate, the E3 ubiquitin ligase HUWE1, a key mediator of apoptotic cell death. SEPARATE enables efficient, unbiased assessment of endopeptidase activity by using a phage-displayed proteome. A record of this paper's Transparent Peer Review process is included in the Supplemental Information.
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PMID:Protease Activity Profiling via Programmable Phage Display of Comprehensive Proteome-Scale Peptide Libraries. 3309 7