Probing the active sites and mechanisms of rat metalloproteases meprin A and B

Greg P. Bertenshaw, James P. Villa, Jeremy A. Hengst, Judith S. Bond

Research output: Contribution to journalArticle

29 Scopus citations

Abstract

Meprin A and B are highly regulated, secreted and cell-surface homo- and hetero-oligomeric enzymes. Meprins are abundantly expressed in kidney and intestine. The multidomain α and β subunits have high sequence identity, however they have very different substrate specificities, oligomerization potentials and are differentially regulated. Here we describe that meprin subunit activities are modulated differently by physico-chemical factors. Homo-oligomeric meprin B had an acidic pH optimum. The low pH protonation indicated the existence of at least two ionizable groups. An additional ionizable group generated a shoulder in the basic pH range. Homo-oligomeric meprin A had a neutral pH optimum and the activity curve revealed that two ionizable groups might be protonated at acidic pH similar to meprin B. Increasing the concentration of salt generally inhibited meprin B activity. Meprin A was inhibited at low salt concentrations but activated as salt was increased. This work has important implications in the elucidation of the catalytic mechanisms of meprins and other metalloproteases. In addition, the activity of meprin oligomers that arise in tissues will be affected by variations in pH and NaCI. This could have profound implications because meprins are exposed to a range of conditions in the extracellular milieu of renal and intestinal tissues and in inflammation and cancer.

Original languageEnglish (US)
Pages (from-to)1175-1183
Number of pages9
JournalBiological Chemistry
Volume383
Issue number7-8
DOIs
StatePublished - Jul 1 2002

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All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Clinical Biochemistry

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