These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Cross-linking of wild-type and mutant alpha 2-antiplasmins to fibrin by activated factor XIII and by a tissue transglutaminase.
    Author: Lee KN, Lee CS, Tae WC, Jackson KW, Christiansen VJ, McKee PA.
    Journal: J Biol Chem; 2000 Dec 01; 275(48):37382-9. PubMed ID: 10958788.
    Abstract:
    Human alpha(2)-antiplasmin (alpha(2)AP), the main inhibitor of plasmin-mediated fibrinolysis, is a substrate for plasma transglutaminase, also termed activated factor XIII (FXIIIa). Of 452 amino acids in alpha(2)AP, only Gln(2) is believed to be a fibrin-cross-linking (or FXIIIa-reactive) site. Kinetic efficiencies (k(cat)/K(m)((app))) of FXIIIa and the guinea pig liver tissue transglutaminase (tTG) and reactivities of Gln substrate sites were compared for recombinant wild-type alpha(2)AP (WT-alpha(2)AP) and Q2A mutant alpha(2)AP (Q2A-alpha(2)AP). [(14)C]Methylamine incorporation showed the k(cat)/K(m)((app)) of FXIIIa to be 3-fold greater than that of tTG for WT-alpha(2)AP. With FXIIIa or tTG catalysis, [(14)C]methylamine was incorporated into Q2A-alpha(2)AP, indicating that WT-alpha(2)AP has more than one Gln cross-linking site. To identify transglutaminase-reactive sites in WT-alpha(2)AP or Q2A-alpha(2)AP, each was labeled with 5-(biotinamido)pentylamine by FXIIIa or tTG catalysis. After each labeled alpha(2)AP was digested by trypsin, sequence and mass analyses of each labeled peptide showed that 4 of 35 Gln residues were labeled with the following reactivities: Gln(2) > Gln(21) > Gln(419) > Gln(447). Q(2)A-alpha(2)AP was also labeled at Gln(21) > Gln(419) > Gln(447), but became cross-linked to fibrin by FXIIIa or tTG at approximately one-tenth the rate for WT-alpha(2)AP. These results show that alpha(2)AP is a better substrate for FXIIIa than for this particular tTG, but that either enzyme involves the same Gln substrate sites in alpha(2)AP and yields the same order of reactivities.
    [Abstract] [Full Text] [Related] [New Search]