The Ca2+ uptake and the (Ca2+ + Mg2+)-dependent ATPase of the porcine coronary-artery smooth-muscle microsomal fraction (‘microsomes’) are only slightly stimulated by calmodulin. The Ca2+ uptake after 2 min in the absence of oxalate, corrected for the ATP-independent binding, increased by a factor of 1.44, whereas the (Ca2+ + Mg2+)-dependent ATPase is stimulated 1.39 times. These findings contrast with the effect observed in human erythrocyte ‘inside-out’ microsomes. In these vesicles calmodulin increases the Ca2+ uptake after 20 min in an oxalate-free medium and the (Ca2+ + Mg2+)-dependent ATPase respectively by a factor of 3.82 and 6.18. The magnitude of the calmodulin stimulation of the Ca2+ transport in coronary-artery microsomes is similar to that observed in heart microsomes.
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Research Article|
September 15 1980
The effect of calmodulin on the active calcium-ion transport and (Ca2+ + Mg2+)-dependent ATPase in microsomal fractions of smooth muscle compared with that in erythrocytes and cardiac muscle
Publisher: Portland Press Ltd
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 1980 London: The Biochemical Society
1980
Biochem J (1980) 190 (3): 827–831.
Citation
F Wuytack, G De Schutter, R Casteels; The effect of calmodulin on the active calcium-ion transport and (Ca2+ + Mg2+)-dependent ATPase in microsomal fractions of smooth muscle compared with that in erythrocytes and cardiac muscle. Biochem J 15 September 1980; 190 (3): 827–831. doi: https://doi.org/10.1042/bj1900827
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