title: Ritonavir does not inhibit calpain in vitro.
abstract: Ritonavir, an inhibitor of HIV-1 protease, has been reported to also inhibit the Ca2+-dependent cysteine protease, calpain. We have investigated these claims with an in vitro study of the effect of ritonavir on the m-calpain and mu-calpain isoforms. Ritonavir failed to block either autolytic or hydrolytic calpain activity, but remained fully capable of inhibiting the HIV-1 protease. Any calpain-related effects of ritonavir in cells must, therefore, arise by a mechanism other than direct inhibition of calpains.
authors.affiliation: Department of Biochemistry, Queen's University, Kingston, Ont., Canada K7L 3N6.
authors.forename: Dominic
authors.initials: D
authors.lastname: Cuerrier
authors.forename: Zilin
authors.initials: Z
authors.lastname: Nie
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Badley
authors.forename: Peter L
authors.initials: PL
authors.lastname: Davies
mesh_terms: D000818:Animals; D002154:Calpain / Q000037:antagonists & inhibitors / Q000378:metabolism*; D016333:HIV Protease / Q000378:metabolism; D006868:Hydrolysis / Q000187:drug effects; D020033:Protein Isoforms / Q000378:metabolism; D051381:Rats; D019438:Ritonavir / Q000494:pharmacology*; D013552:Swine
chemical_list: D020033:Protein Isoforms; D002154:Calpain; C449000:m-calpain; C449002:mu-calpain; D016333:HIV Protease; D019438:Ritonavir