Purification from Dictyostelium discoideum of a low-molecular-weight myosin that resembles myosin I from Acanthamoeba castellanii

G. P. Cote, J. P. Albanesi, T. Ueno, J. A. Hammer, E. D. Korn

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A low-molecular-weight myosin has been purified 1500-fold from extracts of Dictyostelium discoideum, based on the increase in K+,EDTA-ATPase specific activity. The purified enzyme resembles the single-headed, low-molecular-weight myosins IA and IB from Acanthamoeba castellanii, and differs from the conventional two-headed, high-molecular-weight myosin previously isolated from Dictyostelium, in several ways. It has higher K+,EDTA-ATPase activity than Ca2+-ATPase activity; it has a native molecular mass of about 150,000 and a single heavy chain of about 117,000; the 117,000-dalton heavy chain is phosphorylated by Acanthamoeba myosin I heavy chain kinase; phosphorylation of its heavy chain enhances its actin-activated Mg2+-ATPase activity; and the 117,000-dalton heavy chain reacts with antibodies raised against the heavy chain of Acanthamoeba myosin IA. None of these properties is shared by the low-molecular-weight active fragments that can be produced by chymotryptic digestion of conventional Dictyostelium myosin. We conclude that Dictyostelium contains an enzyme of the myosin I type previously isolated only from Acanthamoeba.

Original languageEnglish (US)
Pages (from-to)4543-4546
Number of pages4
JournalJournal of Biological Chemistry
Issue number8
Publication statusPublished - 1985


ASJC Scopus subject areas

  • Biochemistry

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