DROSOPHILA CAMP-DEPENDENT PROTEIN-KINASE

1 January 1984

journal article
research article

Vol. 259 (21) , 3049-3055

Abstract

CAMP-dependent protein kinase was purified to homogeneity from adult bodies D. melanogster. It is tetrameric in structure with 2 regulatory and 2 catalytic subunits that dissociate when activated by cAMP. The regulatory subunit exists in phospho and dephospho forms, which have electrophoretic mobilities in sodium dodecyl sulfate-polyacrylamide gels corresponding to MW = 58,000 and 52,000, respectively. The catalytic subunit has a MW of 40,000. The holenzyme has a Stokes radius of 4.7 nm. The Km for activation by cAMP is substrate-dependent with Km values of 20 nM with histone H2B and 100 nM with the peptide, Leu-Arg-Arg-Ala-Ser-Leu-Gly. These physical and kinetic properties are very similar to those of the bovine heart Type II cAMP-dependent protein kinase. A Drosophila Type I cAMP-dependent protein kinase was also found in larval stages and during the first half of pupation but was absent in embryos and adults. The fly Type II enzyme was present in all developmental stages. Three regions of the Drosophila genome were found which, when present in 3 copies, significantly alter the specific activity of cAMP-dependent protein kinase. These are located at 29F-33F (30% increase), 46A-50C (17% increase) and 66B-67D (16% decrease).

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