Cleavage of phosphorylase kinase and calcium-free calmodulin by HIV-1 protease |
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Authors: | H Daube A Billich K Mann H J Schramm |
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Institution: | Max-Planck-Institut für Biochemie, Martinsried bei München, Germany. |
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Abstract: | Phosphorylase kinase and calcium-free calmodulin are digested by human immunodeficiency virus-1 protease. In phosphorylase kinase, the alpha subunit is preferentially hydrolyzed at arg748-val749. The beta subunit is cleaved only slowly at leu678-pro679, and calmodulin, the integral delta subunit of phosphorylase kinase, is not cleaved at all. However, free calmodulin in the calcium-depleted form showed to be a good substrate for the protease. Here the cleavage occurs at phe65-pro66 and met71-met72. This fast hydrolysis of free calmodulin can be blocked by micromolar concentrations of Ca2+ or millimolar concentrations of Mg2+. |
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