Acanthamoeba Myosin
Year: 1973
Type: article
Abstract: An ATPase that accounts for about 0.3% of the total cell protein has been isolated in 90% purity from Acanthamoeba castellanii. The enzyme has been identified as a myosin-like ATPase by the following criteria. Maximal enzymatic activity occurs in the presence of EDTA and 0.5 m KCl, and is only 10 to 20% as high in the presence of Ca2+ and less than 1% in the presence of Mg2+. The Mg2+ ATPase is activated by actin under physiological conditions and the enzyme binds to actin filaments in the absence but not in the presence of ATP. Acanthamoeba myosin shows some activity toward nucleoside triphosphates other than ATP but does not hydrolyze ADP or AMP. In contrast to myosins from other sources, Acanthamoeba myosin is soluble under physiological conditions, and its partition coefficient on gel filtration suggests a native molecular weight of about 180,000, which is smaller than other myosins. Several different experiments show that the isolated molecule is not formed by proteolytic cleavage of a larger native protein. The purified enzyme consists of three polypeptide chains with molecular weights of 140,000, 16,000, and 14,000. The amino composition is remarkable for the absence of cysteine.
Source: Journal of Biological Chemistry
Authors: Thomas D. Pollard, Edward D. Korn
Institution: National Heart, Lung, and Blood Institute
Language: English
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: hybrid
Estimated APC paid: $3,430
OpenAlex ID: W1651271817