Altered isoelectric focusing of alpha 2-macroglobulin from plasma of patients with diabetes mellitus.

Publication/Presentation Date

7-30-1985

Abstract

Plasma from both type I and type II patients with diabetes mellitus displayed elevated alpha 2-macroglobulin trypsin-binding activity relative to normals. Column isoelectric focusing indicated that the average isoelectric point (pI) of the major form of crude alpha 2-macroglobulin was 6.6, 5.9, and 6.2 for normal, type I and type II subjects, respectively. Focused crude diabetic alpha 2-macroglobulin displayed significantly less recovered trypsin-binding activity relative to controls, particularly above a pI value of 6.0. Following preincubation with trypsin, the crude diabetic alpha 2-macroglobulin displayed a single isoelectric form (pI value of 5.3-5.5) and a substantial increase in recovered activity which were both comparable to normal alpha 2-macroglobulin. Purified alpha 2-macroglobulin from both normal and diabetic subjects displayed similar focusing profiles having a distribution of three forms with a pI value of 5.3-5.4 for the principal form. Trypsin-preincubated samples of purified alpha 2-macroglobulin displayed a single form with a pI value of 5.5-6.0. Preincubation of purified normal or diabetic alpha 2-macroglobulin with a plasma preparation devoid of alpha 2-macroglobulin from normal or diabetic plasma resulted in significantly lowered recovery of activity. All of the above studies suggest that the altered focusing properties observed for crude diabetic alpha 2-macroglobulin are due to components of the plasma rather than to alpha 2-macroglobulin itself.

Volume

150

Issue

1

First Page

21

Last Page

29

ISSN

0009-8981

Disciplines

Medicine and Health Sciences

PubMedID

2412734

Department(s)

Department of Medicine

Document Type

Article

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