Contractile proteins from the tomato
- 1 April 1980
- journal article
- Published by Canadian Science Publishing in Canadian Journal of Botany
- Vol. 58 (7) , 797-801
- https://doi.org/10.1139/b80-101
Abstract
Proteins exhibiting all of the basic structural and biochemical characteristics of actin and myosin have been isolated from the parenchymal cells of the fruit of the tomato, Lycopersicon esculentum. Crude cytoplasmic extracts of these cells contain filaments that can be decorated by rabbit skeletal muscle myosin subfragment-1 (S-1). Polymerized tomato actin activates the Mg2+–ATPase of both skeletal and tomato myosin at physiological ionic strength. Tomato actin comigrates with skeletal actin on sodium dodecyl sulfate polyacrylamide gels (SDS-PAGE) indicating an apparent molecular weight of 45 000. High ionic strength extracts of tomato contain a myosin whose ATPase activity in 0.5 M KCl is maximal in the presence of K+-ethylenediaminetetraacetic acid (K+-EDTA) and is inhibited by Mg2+. Tomato myosin interacts with skeletal F-actin to form an actomyosin complex that can be dissociated by ATP. At low ionic strength the Mg2+–ATPase of the myosin can be activated by actin.Keywords
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