Linked Life Data

11994472

Source:http://linkedlifedata.com/resource/pubmed/id/11994472

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
2002-5-7
pubmed:abstractText
fgl2 prothrombinase, by its ability to generate thrombin, has been shown to be pivotal to the pathogenesis of viral-induced hepatitis, cytokine-induced fetal loss syndrome, and xeno- and allograft rejection. In this study, the molecular basis of fgl2 prothrombinase activity was examined in detail. Purified fgl2 protein generated in a baculovirus expression system had no measurable prothrombinase activity, whereas the activity was restored when the purified protein was reconstituted into phosphatidyl-L-serine-containing vesicles. Reconstituted fgl2 catalyzed the cleavage of human prothrombin to thrombin with kinetics consistent with a first order reaction, with an apparent V(max) value of 6 mol/min/mol fgl2 and an apparent K(m) value for prothrombin of 8.3 microM. The catalytic activity was totally dependent on calcium, and factor Va (500 nM) enhanced the catalytic efficiency of fgl2 by increasing the apparent V(max) value to 3670 mol/min/mol fgl2 and decreasing the apparent K(m) value for prothrombin to 7.2 microM. By a combination of site-directed mutagenesis and production of truncated proteins, it was clearly shown that residue Ser(89) was critical for the prothrombinase activity of fgl2. Furthermore, fgl2 prothrombinase activity was not inhibited by antithrombin III, soybean trypsin inhibitor, 4-aminobenzamidine, aprotinin, or phenylmethylsulfonyl fluoride, whereas diisopropylfluorophosphate completely abrogated the activity. In this work we provide direct evidence that fgl2 cleaves prothrombin to thrombin consistent with serine protease activity and requires calcium, phospholipids, and factor Va for its full activity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0022-1767
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
168
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5170-7
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:11994472-Animals, pubmed-meshheading:11994472-Baculoviridae, pubmed-meshheading:11994472-Blood Coagulation, pubmed-meshheading:11994472-CHO Cells, pubmed-meshheading:11994472-Calcium, pubmed-meshheading:11994472-Cricetinae, pubmed-meshheading:11994472-Enzyme Activation, pubmed-meshheading:11994472-Female, pubmed-meshheading:11994472-Fibrinogen, pubmed-meshheading:11994472-Kinetics, pubmed-meshheading:11994472-Macrophages, Peritoneal, pubmed-meshheading:11994472-Mice, pubmed-meshheading:11994472-Mice, Inbred BALB C, pubmed-meshheading:11994472-Murine hepatitis virus, pubmed-meshheading:11994472-Mutagenesis, Site-Directed, pubmed-meshheading:11994472-Phospholipids, pubmed-meshheading:11994472-Recombinant Proteins, pubmed-meshheading:11994472-Serine, pubmed-meshheading:11994472-Spodoptera, pubmed-meshheading:11994472-Thrombin, pubmed-meshheading:11994472-Thromboplastin
pubmed:year
2002
pubmed:articleTitle
Kinetic analysis of a unique direct prothrombinase, fgl2, and identification of a serine residue critical for the prothrombinase activity.
pubmed:affiliation
Multi Organ Transplant Program, Toronto General Hospital and University of Toronto, 621 University Avenue 10th Floor, Room 116, Toronto, Ontario M5G 2C4, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't