Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.1 (chymotrypsin)
 10,938 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The differential cleavage of surface proteins of Borrelia burgdorferi IRS strains by several proteases was examined. Proteinase K, trypsin, chymotrypsin and thermolysin all cleaved the outer surface protein B (OspB) to undetectable levels by Coomassie Brilliant Blue staining, whereas some residual protein was detected by immunoblotting with polyclonal and monoclonal antibodies. Not even antigenic fragments were detectable by immunoblotting with 1A8 monoclonal antibody reactive with OspB. Less effective or ineffective was the cleavage of OspB by V8 protease and proteinase A, respectively. The outer surface protein A was cleaved only by proteinase K. The effect of trypsin on borreliae viability and adhesion to cultured cells was also studied. The trypsin treatment of borreliae did not impair the viability of organisms which continued to synthesize the cleaved OspB. The attachment of B. burgdorferi to HEp-2 cells was reduced by 41% after treatment with trypsin, whereas preincubation of borreliae with monoclonal antibody 1A8 and guinea pig immune serum reduced the adhesion of borreliae to the cells by 32% and 87%, respectively.
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PMID:Differential cleavage of surface proteins of Borrelia burgdorferi by proteases. 160 94

The complete amino acid sequence of the acid proteinase A, a non-pepsin type acid proteinase from the fungus Aspergillus niger var. macrosporus, was determined by protein sequencing. The enzyme was first dissociated at pH 8.5 into a light (L) chain and a heavy (H) chain, and the L chain was sequenced completely. Further sequencing was performed with the reduced and pyridylethylated or aminoethylated derivative of the whole protein, using peptides obtained by digestions with Staphylococcus aureus V8 protease, trypsin, chymotrypsin, and lysylendopeptidase. The location of the two disulfide bonds was determined by analysis of cystine-containing peptides obtained from a chymotryptic digest of the unmodified protein. These results established that the protein consists of a 39-residue L chain and a 173-residue H chain that associate noncovalently to form the native enzyme of 212 residues (Mr 22,265). This is, to our knowledge, the first time that such a protein with a rather short peptide chain associated noncovalently has been found. No sequence homology is found with other acid or aspartic proteinases, except for Scytalidium lignicolum acid proteinase B, an enzyme unrelated to pepsin by sequence, which has about 50% identity with the present enzyme. These two enzymes, however, are remarkably different from each other in some structural features.
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PMID:The primary structure of Aspergillus niger acid proteinase A. 191 59

One of the esteroproteinases present in the submandibular glands of female mice was purified and characterized. The enzyme, designated proteinase F in this report, had a pI value of 4.6 and a molecular weight of 27600, being comprised of two subunits of 10000 and 18000 daltons. The amino acid composition of proteinase F resembled that of the epidermal growth factor-binding protein, but antiserum against proteinase F only reacted weakly against the binding protein. Proteinase F had an optimum pH at around 9.0 and was strongly inhibited by Cu2+ and Hg2+ (42 and 76% inhibition, respectively, at a concentration of 4 x 10(-6) M). It was also inhibited by aprotinin, phenylmethylsulfonylfluoride, iodoacetamide, leupeptin, antipain, and benzamidine but neither by trypsin inhibitors from pancrease, soybean, or ovomucoid, nor by TLCK, TPCK, and epsilon-amino-n-caproic acid. Although its actual physiological function has yet to be determined, these properties indicate that proteinase F is a new enzyme, being distinguished from known proteinases, kallikrein, plasmin, trypsin, chymotrypsin, tonin, angiotensin-converting enzyme, proteinase A (beta-nerve growth factor endopeptidase), proteinase D (epidermal growth factor-binding protein), P-esterase, renin A, and renin C. Proteinase F was present in the submandibular glands of female mice more abundantly than in those of males, but it increased in males following castration. Thus, proteinase F appears to be affected by male hormones in vivo.
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PMID:A new esteroproteinase (proteinase F) from the submandibular glands of female mice. 633 33

Chymotrypsin/elastase inhibitor-1 is a member of the Ascaris family of serine protease inhibitors. It is characterized by five disulfide bridges in a polypeptide chain of 63 amino acids. The disulfide bridge pairing was resolved by cleavage at methionyl residues with cyanogen bromide followed by a combination of proteolytic digestions with glycyl endopeptidase, Staphylococcal serine proteinase, and submandibular proteinase A. The peptides were separated on a reverse-phase HPLC column. Amino acid analyses and N-terminal microsequencing of the cystine containing peptides revealed the disulfide bridge pairing between residues 5-54, 15-29, 18-38, 22-33, and 40-60. The disulfide bridge pairing of other members of this unique family was also assigned. The major isoform, trypsin inhibitor-1, and chymotrypsin/elastase inhibitor-4 share the same disulfide bridge pattern. These results strongly suggest that all members of the Ascaris family of serine protease inhibitors have the same disulfide bridge pattern which represents a unique motif.
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PMID:The serine protease inhibitor family from Ascaris suum: chemical determination of the five disulfide bridges. 851 22

A new protease inhibitor was purified to apparent homogeneity from a culture medium of Photorhabdus luminescens by ammonium sulfate precipitation and preparative isoelectric focusing followed by affinity chromatography. Ph. luminescens, a bacterium symbiotically associated with the insect-parasitic nematode Heterorhabditis bacteriophora, exists in two morphologically distinguishable phases (primary and secondary). It appears that only the secondary-phase bacterium produces this protease inhibitor. The protease inhibitor has an M:(r) of approximately 12000 as determined by SDS-PAGE. Its activity is stable over a pH range of 3.5-11 and at temperatures below 50 degrees C. The N-terminal 16 amino acids of the protease inhibitor were determined as STGIVTFKND(X)GEDIV and have a very high sequence homology with the N-terminal region of an endogenous inhibitor (IA-1) from the fruiting bodies of an edible mushroom, Pleurotus ostreatus. The purified protease inhibitor inactivated the homologous protease with an almost 1:1 stoichiometry. It also inhibited proteases from a related insect-nematode-symbiotic bacterium, Xenorhabdus nematophila. Interestingly, when present at a molar ratio of 5 to 1, this new protease inhibitor completely inactivated the activity of both trypsin and elastase. The activity of proteinase A and cathepsin G was partially inhibited by this bacterial protease inhibitor, but it had no effect on chymotrypsin, subtilisin, thermolysin and cathepsins B and D. The newly isolated protease inhibitor from the secondary-phase bacteria and its specific inhibition of its own protease provides an explanation as to why previous investigators failed to detect the presence of protease activity in the secondary-phase bacteria. The functional implications of the protease inhibitor are also discussed in relation to the physiology of nematode-symbiotic bacteria.
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PMID:A new broad-spectrum protease inhibitor from the entomopathogenic bacterium Photorhabdus luminescens. 1110 72