Distribution of the methyl acceptor proteins within platelet granules.

Fractionation of platelet alpha-granules and dense bodies demonstrated that methyl acceptor proteins (MAP) were present in the alpha-granule fractions, but seemed to be low or absent in the dense body fraction. MAP activity in four intragranular proteins (albumin, fibrinogen, beta-thromboglobulin and platelet derived growth factor) was low or absent and could not explain the difference in methyl acceptor proteins distribution between alpha-granules and dense bodies.