The function of the human factor V carbohydrate moiety in blood coagulation.
Human factor V was subjected to desialation and deglycosylation to investigate the function of the molecular carbohydrate moiety. Removal of 90% of the sialic acid residues resulted in a 1.5-2-fold increase in clotting activity, and up to 70% deglycosylation in a concurrent decrease in clotting activity. Desialation had no effect on thrombin-induced activation, whereas deglycosylated factor V activation was impaired. Lectin-blot experiments with sialic-acid-specific Limax flavus agglutinin (LFA), galactose-specific Ricinus communis agglutinin (RCA-II) and mannose-specific concanavalin A on thrombin-induced factor V fragments revealed the presence of carbohydrate residues in fragments B, C1, D and F1F2. Interestingly, sialic acid was present in C1 whilst galactose was not detectable. Fragment F1F2 contained terminal galactose residues. LFA and RCA-II inhibited the procoagulant activity of native factor V and of desialated factor V respectively. These investigations distinctly indicate the important role of the human factor V carbohydrate moiety in the process of blood coagulation.
D001777:Blood Coagulation; D004789:Enzyme Activation; D005165:Factor V / Q000302:isolation & purification / Q000502:physiology*; D006026:Glycoside Hydrolases; D006801:Humans; D037102:Lectins; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D008970:Molecular Weight; D009439:Neuraminidase; D012794:Sialic Acids / Q000032:analysis; D013329:Structure-Activity Relationship; D013917:Thrombin / Q000378:metabolism
D037102:Lectins; D012794:Sialic Acids; D005165:Factor V; D006026:Glycoside Hydrolases; D009439:Neuraminidase; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D013917:Thrombin