期刊名称：Journal of Clinical Biochemistry and Nutrition
印刷版ISSN：0912-0009
电子版ISSN：1880-5086
出版年度：1991
卷号：10
期号：1
页码：1-14
DOI：10.3164/jcbn.10.1
出版社：The Society for Free Radical Research Japan
摘要：The kinetic properties of Mg2+-ATPase of bovine brain kinesin in the steady-state were studied in the absence of microtubules. A double-reciprocal plot of kinesin Mg2+-ATPase activity vs. ATP concentration indicated two distinct K m values, 128 and 3.3μM. ATPase activity decreased with increase in pH from 6.0 to 7.0, increased as the pH was increased to 8.0, and then gradually decreased above pH 8.0. The rate of ATP hydrolysis was also affected by the KCl concentration. ATPase activity decreased with an increase in KCl concentration from 15 to 50mM, increased as the KCl concentration was increased further, and then decreased when KCl exceeded 200mM. From an Arrhenius plot of temperature dependency of Mg2+-ATPase activity, activation energy was estimated to be 25.3J/mol between 45 and 23°C and 87.9J/mol between 23 and 6°C. Both heavy and light chains in kinesin were phosphorylated by the catalytic subunit of cyclic AMP-dependent protein kinase, which resulted in a 2.8-fold activation of Mg2+-ATPase in the absence of microtubules. These properties are more like smooth muscle myosin than skeletal muscle myosin.
