Abstract
The maximal rates of the protein kinase (ATP: protein phosphotransferase, EC 2.7.1.37) reaction studied with chicken egg yolk phosvitin as substrate are dependent on the level of dephosphorylation of phosvitin. 30% dephospho-phosvitin gives the optimal initial rates. With varying levels of dephosphorylation, the apparent Km for the substrate also changes in a biphasic manner. If this factor is taken into account, and a suitable adjustment is made for the concentration of dephospho-phosvitin in the reaction, it is possible to achieve maximal rates for the kinase reaction with phosvitin preparations of varying levels of dephosphorylation. Such a consideration is important for comparing the results of protein kinase studies using phosvitin as the substrate.
Original language | English (US) |
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Pages (from-to) | 80-83 |
Number of pages | 4 |
Journal | BBA - Enzymology |
Volume | 377 |
Issue number | 1 |
DOIs | |
State | Published - Jan 23 1975 |
Bibliographical note
Funding Information:This work is supported in part by research grant No. CA-15062 from N.C.I., N.I.H., U.S.P.H.S.