Differential effects of aluminum ion on smooth muscle calpain I and calpain II activities.
1. In millimolar Ca2+, smooth muscle calpains I and II were inhibited by aluminum ion. 2. At sub-millimolar Ca2+, calpain II, but not calpain I, was activated by low millimolar aluminum ion. 3. Calpastatin inhibited aluminum ion-activated calpain II. 4. Aluminum ion-activated and Ca(2+)-activated calpain II gave almost identical patterns of desmin cleavage. 5. Aluminum-activated calpain II, unlike the Ca(2+)-activated enzyme, did not autolyze and retained its proteolytic activity over extended periods of time.
Zhang
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H
Department of Chemistry, Ohio University, Athens 45701.
Johnson
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P
D000535:Aluminum / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000494:pharmacology; D002154:Calpain / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D002645:Chickens; D009130:Muscle, Smooth / Q000187:drug effects* / Q000201:enzymology; D013379:Substrate Specificity
D002135:Calcium-Binding Proteins; C033668:calpastatin; D000535:Aluminum; D002154:Calpain; D002118:Calcium