Linked Life Data

2248955

Source:http://linkedlifedata.com/resource/pubmed/id/2248955

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
40
pubmed:dateCreated
1991-1-15
pubmed:abstractText
Previous studies indicated that factor VIIa, in complex with tissue factor, readily activates either factor X or factor IX in the presence of calcium ions. In order to assess the relative physiological importance of the activation of factor IX versus the activation of factor X by recombinant factor VIIa, we have obtained steady-state kinetic parameters for the factor VIIa catalyzed activation of factor IX and factor X under a variety of cofactor conditions that include calcium alone, calcium and phospholipids, calcium, phospholipids, and tissue factor apoprotein, and calcium and cell-surface tissue factor. Calcium alone stimulated the activation of factors IX and X by factor VIIa maximally at 1 and 2.5 mM, respectively. In the presence of 25 microM phospholipids, maximal rates of factor IX and factor X activation were achieved at 2.5-5 mM calcium. With calcium alone, or with phospholipid and calcium, the initial rates of factor IX activation by factor VIIa were significantly higher than that observed for factor X. Kinetic studies revealed that the Km for the factor VIIa catalyzed activation of factor IX was essentially constant in the presence of 5 mM calcium and 1-500 microM phospholipid, whereas the Km for factor X activation varied with phospholipid concentration, reaching a minimum at 7-20 microM phospholipid. At all concentrations of added phospholipid, the kcat/Km ratio for the activation of factor IX by factor VIIa appeared to be considerably greater than that observed for the activation of factor X.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
9
pubmed:volume
29
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
9418-25
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Proteolytic activation of human factors IX and X by recombinant human factor VIIa: effects of calcium, phospholipids, and tissue factor.
pubmed:affiliation
Department of Pathology, University of New Mexico School of Medicine, Albuquerque 87131.
pubmed:publicationType
Journal Article, In Vitro, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't