Linked Life Data

8797081

Source:http://linkedlifedata.com/resource/pubmed/id/8797081

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1997-4-1
pubmed:databankReference
pubmed:abstractText
A thrombin-like enzyme, calobin, has been purified to homogeneity from the venom of Agkistrodon caliginosus by a procedure involving Bio-Gel P-100, Mono S, and Pro-RPC. The enzyme was identified as a monomer with a molecular weight of 34,000 on SDS-PAGE, and its isoelectric point was 6.2. Calobin acted on fibrinogen to form fibrin with a specific activity of 226 NIH equivalent units, and also exhibited arginine esterase activity. The enzyme predominantly cleaved the alpha-chain of fibrinogen with little degradation of the beta-chain. It contained abundant asparagine/aspartic acid residues, but very few tyrosine or methionine residues. The proteolytic activity of the enzyme with TAME as a substrate was higher than that of thrombin. However, it showed neither lysine esterase nor caseinolytic activity. The enzyme activity was strongly inhibited by PMSF, and moderately by benzamidine and soybean trypsin inhibitor, indicating it is a serine protease. On the other hand, the enzyme activity was not inhibited by hirudin or aprotinin. cDNA (1.6 kb) for calobin has been cloned from an A. caliginosus cDNA library. The cDNA sequence indicates that calobin is synthesized as a pre-zymogen of 262 amino acids, including a putative secretory signal peptide of 18 amino acids and a proposed zymogen peptide of 6 amino acid residues. The cDNA sequence encodes a 238-amino acid residue molecule exhibiting strong amino acid sequence homology to those of ancrod, batroxobin, and flavoxobin isolated from other snake venoms. Calobin contains 12 cysteine residues. As judged on alignment of the amino acid sequences of other thrombin-like enzymes (batroxobin, ancrod, and flavoxobin), calobin constitute the formation of six disulfide bridges. Amino acid residues, His43, Asp88, and Ser182, which are thought to be the catalytic active site are highly conserved. As calobin is a glycoprotein, its possible glycosylation site, Asn-X-Thr, is located at amino acid residues 81-83.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-924X
pubmed:author
pubmed:issnType
Print
pubmed:volume
119
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
835-43
pubmed:dateRevised
2007-12-19
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Purification and molecular cloning of calobin, a thrombin-like enzyme from Agkistrodon caliginosus (Korean viper).
pubmed:affiliation
Natural Products Research Institute, Seoul National University, Korea.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't