MECHANISM OF RELEASE OF ACTIVE ALPHA-SUBUNIT FROM DIMERIC ALPHA-BETA AVIAN-MYELOBLASTOSIS VIRUS-DNA POLYMERASE

Storage of the dimeric (.alpha..beta.) form of avian myeloblastosis virus DNA polymerase in glycerol resulted in the release of the smaller .alpha. subunit, as detected by glycerol gradient sedimentation. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of enzyme stored in glycerol showed the concomitant appearance of several polypeptides and a lowering in the level of both .beta. and .alpha. components. This reduction appears to be the result of cleavages introduced by traces of hydrolytic activity present in glycerol samples. An enhancement of .alpha. subunit released, as detected by activity profile, was also achieved upon direct but limited exposure of purified avian myeloblastosis virus DNA polymerase to CM-cellulose-bound trypsin matrix. Electrophoretic analysis of digested enzyme revealed a progressive fragmentation, with simultaneous increase in the .alpha. subunit and decrease in the .beta. subunit.