Differential isoelectric focusing properties of crude and purified human α2-macroglobulin and α2-macroglobulin-proteinase complexes

Stephen A. Back, Jack A. Alhadeff

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6 Scopus citations


The isoelectric focusing (IEF) properties of human α2-macroglobulin (α2M) and α2M-proteinase complexes from crude and partially purified preparations were studied by column IEF. The average isoclectric point (pI) of the major form was 6.5 for α2M from crude plasma but was 5.3 for purified samples. Following preincubation with either trypsin, chymotrypsin or pancreatic elastase the crude α2M-proteinase complexes displayed pI values ranging from 5.3 to 6.1 and the purified α2M-proteinase complexes ranged from ph 6.0 to 6.1. A comparison of recoveries for focused crude or purified α2M and trypsin-preincubated α2M indicated enhanced recovery for the trypsin-preincubated samples suggesting that the binding of the proteinase enhances the stability of α2M. α2M thus displays column IEF properties which appear to be dependent upon the state of purity of the molecule. These findings are of particular significance to investigators concerned with using expressions of altered α2M electrophoretic patterns for clinical diagnostic purposes in such diseases as multiple sclerosis, diabetes and cystic fibrosis.

Original languageEnglish (US)
Pages (from-to)43-51
Number of pages9
JournalJournal of Chromatography B: Biomedical Sciences and Applications
Issue numberC
StatePublished - 1983
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)


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