Effect of herbimycin A, an inhibitor of tyrosine kinase, on protein tyrosine kinase activity and phosphotyrosyl proteins of Ph1-positive leukemia cells.

Herbimycin A, a benzoquinonoid anasamycin antibiotic, preferentially inhibited the in vitro growth of Ph1-positive leukemia cell lines. On the other hand, genistein, which was developed as an inhibitor of receptor-type tyrosine kinase, and other protein kinase inhibitors showed no selective inhibition of Ph1-positive leukemia cell growth. Herbimycin A also displayed an abrogative effect on the transformation of murine hematopoietic cells by transfection with a bcr/abl oncoprotein-expressing retroviral vector.

Reconstitution of membrane proteins: sequential incorporation of integral membrane proteins into preformed lipid bilayers.

Several integral membrane proteins can be inserted sequentially into preformed unilamellar vesicles (ULV's) composed of dimyristoylphosphatidylcholine (DMPC) and cholesterol in a gel phase. Thus, proteoliposomes of DMPC, cholesterol, and bacteriorhodopsin from Halobacterium halobium rapidly incorporate UDPglucuronosyltransferase (EC 2.4.