Linked Life Data

6193813

Source:http://linkedlifedata.com/resource/pubmed/id/6193813

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1983-11-23
pubmed:abstractText
The binding of trypsin to alpha 2-macroglobulin, the appearance of free beta-cysteinyl thiol groups of the formed complexes, the steady-state kinetics of their enzymic hydrolysis of carbobenzoxy-L-valyl-glycyl-L-arginyl-4-nitroanilide and finally their reactions with soybean trypsin inhibitor leading to the formation of ternary alpha 2-macroglobulin-trypsin-soybean trypsin inhibitor complexes were investigated. Each alpha 2-macroglobulin molecule binds two trypsin tightly; the dissociation constants were found to be unmeasureably small, but the extent of formation of 1:1 and 1:2 complexes at different molar ratios of alpha 2-macroglobulin to trypsin as determined from the appearance of thiol groups clearly indicated that binding of trypsin to alpha 2-macroglobulin shows negative cooperativity. Binding of the first trypsin makes the access of the second less easy. The kinetic results showed a decrease of the kc/Km value of hydrolysis of the tripeptide substrate by approx. 4-fold compared to that of free trypsin for each alpha 2-macroglobulin-bound trypsin. Here no differences were seen between the bound trypsins. The analysis of the reactions between the alpha 2-macroglobulin-trypsin complexes and soybean trypsin inhibitor shows that ternary complexes do form, although slowly, and that two processes occur, not only when 1:2 complexes but also when 1:1 complexes react with soybean trypsin inhibitor. Soybean trypsin inhibitor apparently discriminates between two distinct binding modes of trypsin to alpha 2-macroglobulin, the covalently and the noncovalently alpha 2-macroglobulin-bound trypsins.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0006-3002
pubmed:author
pubmed:issnType
Print
pubmed:day
28
pubmed:volume
747
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
263-75
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1983
pubmed:articleTitle
Enzymatic properties of alpha 2-macroglobulin-proteinase complexes. Apparent discrimination between covalently and noncovalently bound trypsin by reaction with soybean trypsin inhibitor.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.