The high molecular weight multicatalytic proteinase, macropain, exists in a latent form in human erythrocytes

Michael J. McGuire, Marci L. McCullough, Dorothy E. Croall, George N. DeMartino

Research output: Contribution to journalArticlepeer-review

98 Scopus citations

Abstract

The high molecular weight multicatalytic proteinase, macropain, has been purified from human erythrocytes in two forms that differ in caseinolytic activity up to 100-fold. Each form has a native molecular weight of 600 000 and is composed of a number of subunits ranging in molecular weights from 35 000 to 21 000. Although the two proteinase forms share a number of electrophoretically indistinguishable subunits, there are also subunits unique to the respective forms. The less active proteinase represents a latent enzyme because it was fully activated by two procedures including dialysis against water and pretreatment with low concentrations of sodium dodecyl sulfate. These procedures caused differential changes in the caseinolytic and two peptidase activities of the proteinase. An Mr 35 000 subunit, characteristic of latent macropain, is immunologically related to at least one of the other components of active macropain and disappeared after proteinase activation by dialysis. Nevertheless, loss of this subunit was not the cause of the increased activity. These results suggest that the proteolytic activity of cells may be regulated by the activation of the latent form of macropain.

Original languageEnglish (US)
Pages (from-to)181-186
Number of pages6
JournalBiochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
Volume995
Issue number2
DOIs
StatePublished - Apr 6 1989

Keywords

  • (Human erythrocyte)
  • Laten form
  • Macropain
  • Multicatalytic proteinase
  • Proteinase

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology

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