Document Detail


The contact activation mechanism in human plasma: activation induced by dextran sulfate.
MedLine Citation:
PMID:  6177360     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Incubation of normal human plasma with dextran sulfate for 7 min at 4 degrees C generates kallikrein amidolytic activity. No kallikrein activity is generated in factor XII or prekallikrein-deficient plasma and only small amounts (8%) in high molecular weight (HMW) kininogen-deficient plasma. Addition of specific antisera directed against prekallikrein or HMW kininogen to normal plasma blocked the generation of kallikrein activity by dextran sulfate. Thus, factor XII, prekallikrein, and HMW kininogen are essential components for optimal activation of prekallikrein. The role of limited proteolysis in the activation of prekallikrein induced by dextran sulfate was studied by adding 125I-prekallikrein to plasma. The generation of kallikrein activity paralleled the proteolytic cleavage of prekallikrein as judged on SDS gels in the presence of reducing agents. The same cleavage fragments were observed as obtained by activation of purified prekallikrein by beta-factor-XIIa. Addition of 131I-HMW kininogen and 125I-factor XII or 131I-HMW kininogen and 125I-prekallikrein to normal plasma followed by activation with dextran sulfate and analysis on SDS gels indicated that the observed cleavage of prekallikrein and HMW kininogen is fast compared to the observed cleavage of factor XII, which is much slower and less extensive. During the first minutes of incubation of normal plasma with dextran sulfate, mainly alpha-factor-XIIa is formed. During prolonged incubation, beta-factor-XIIa is also formed.
Authors:
F van der Graaf; F J Keus; R A Vlooswijk; B N Bouma
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Blood     Volume:  59     ISSN:  0006-4971     ISO Abbreviation:  Blood     Publication Date:  1982 Jun 
Date Detail:
Created Date:  1982-08-07     Completed Date:  1982-08-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  7603509     Medline TA:  Blood     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1225-33     Citation Subset:  AIM; IM    
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MeSH Terms
Descriptor/Qualifier:
Dextran Sulfate
Dextrans / pharmacology*
Factor XII / physiology
Humans
Kallikreins / blood*,  physiology*
Kinetics
Kininogens / physiology
Molecular Weight
Prekallikrein / physiology*
Chemical
Reg. No./Substance:
0/Kininogens; 9001-30-3/Factor XII; 9004-54-0/Dextrans; 9042-14-2/Dextran Sulfate; 9055-02-1/Prekallikrein; EC 3.4.21.-/Kallikreins

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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