The intriguing world of prothrombin activators from snake venom.
Activation of prothrombin to mature thrombin occurs by the proteolytic action of the prothrombinase complex consisting of a serine proteinase factor Xa, and cofactors factor Va, Ca(2+) ions and phospholipids. Several exogenous prothrombin activators are found in snake venom. They are classified into four groups based on their cofactor requirements. Group A and B prothrombin activators are metalloproteinases whereas group C and D prothrombin activators are serine proteinases. Group C prothrombin activators resemble the mammalian factor Xa-factor Va complex, while Group D activators are structurally and functionally similar to factor Xa. This review provides a detailed description of the current knowledge on all prothrombin activators and highlights several intriguing questions that are yet to be answered.
Kini
R Manjunatha
RM
Protein Science Laboratory, Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore. dbskinim@nus.edu.sg
D000818:Animals; D002118:Calcium / Q000378:metabolism; D004789:Enzyme Activation / Q000502:physiology; D005165:Factor V / Q000378:metabolism*; D015943:Factor Va / Q000378:metabolism; D015951:Factor Xa / Q000378:metabolism*; D045726:Metalloproteases / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D011516:Prothrombin / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000378:metabolism*; D012910:Snake Venoms / Q000201:enzymology*; D012911:Snakes; D013329:Structure-Activity Relationship
D010743:Phospholipids; D012910:Snake Venoms; C022475:prothrombinase complex; D015943:Factor Va; D005165:Factor V; D011516:Prothrombin; D045726:Metalloproteases; D012697:Serine Endopeptidases; D015951:Factor Xa; D002118:Calcium