title: Functional activities and nonenzymatic glycosylation of plasma proteinase inhibitors in diabetes.
abstract: The functional activity of three of the major plasma protease inhibitors, alpha 1-proteinase inhibitor, antithrombin III and alpha 2-antiplasmin, has been measured in a series of persons with diabetes mellitus and compared with healthy controls. The mean specific functional activity of both diabetic plasma antithrombin III (50.8 +/- 7.0 U/mg) and alpha 1-proteinase inhibitor (35.3 +/- 5.6 mU/mg) was found to be significantly lower than in healthy controls (57.9 +/- 6.0 U/mg) and (42.2 +/- 10.7 mU/mg). No difference was detected in alpha 2-antiplasmin activity or levels. The glycosylated protein fraction of 83% of diabetic plasmas showed the presence of less than 1% of the total alpha 1-proteinase inhibitor when isolated by phenylboronate affinity chromatography. Incubation of normal plasma with 250 nmol/l glucose (a level approximately 6 X higher than encountered in uncontrolled diabetes) resulted in a 17% and 6% decrease in antithrombin III and alpha 1-proteinase inhibitor activities. We conclude that the decrease in specific activity of alpha 1-proteinase inhibitor is not related to nonenzymatic glycosylation, but the decrease in antithrombin III specific activity may be related.
mesh_terms: D000328:Adult; D000990:Antithrombin III / Q000378:metabolism; D001798:Blood Proteins / Q000378:metabolism; D003920:Diabetes Mellitus / Q000097:blood*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000097:blood; D005260:Female; D006031:Glycosylation; D006801:Humans; D007122:Immunoelectrophoresis; D008297:Male; D008875:Middle Aged; D011480:Protease Inhibitors / Q000097:blood*; D000515:alpha 1-Antitrypsin; D000979:alpha-2-Antiplasmin / Q000378:metabolism
chemical_list: D001798:Blood Proteins; D011480:Protease Inhibitors; D000515:alpha 1-Antitrypsin; D000979:alpha-2-Antiplasmin; D000990:Antithrombin III