Apparent initial binding rate of calcium by canine cardiac-relaxing system.
Apparent initial binding rate of calcium by canine cardiac-relaxing system.
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犬心脏舒张系统对钙的表观初始结合率。
DOI：
10.1152/ajplegacy.1972.223.3.608
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发表时间：
1972
期刊：
影响因子：
--
通讯作者：
A. Schwartz
中科院分区：
文献类型：
--
作者：
W. McCollum;H. R. Besch;M. Entman;A. Schwartz
麦科勒姆，威廉b ., hr besch, jr ., mark l. entman和Arnold schwartz。犬心脏放松系统对钙的表观初始结合率。点。[j] .中国生物医学工程学报，2009(3):444 - 444。1972年，用停流分光光度法测定犬心脏组织的囊泡部分的初始钙结合率（稳态前）。这些小泡可能是肌浆网的组成部分，因此与肌肉松弛有关。对松弛系统的分离程序进行了改进，使制备在25℃下每毫克蛋白质结合60-90 nmol钙（依赖于ATP）。新鲜制备每毫秒结合每毫克蛋白质至少130 pmol钙。在200毫秒内的结合量为15.5毫摩尔/毫克蛋白质或37℃时每克湿重心肌约100毫摩尔钙。结合能力和钙结合率与该水泡部分在心肌松弛中的假设作用一致。stopped-flow;骨螺紫;肌浆网;心脏肌浆网（SR）在功能心肌的主动松弛中可能发挥的核心作用现已得到充分证实（1,3 - 6,11,17,18,22）。松弛系统（CRS）由主要来源于心脏肌浆网的囊泡组成，能够结合一定量的钙，从而使完全激活的纤维松弛（4,5,9,18,22）。犬心肌在体内大约200毫秒（25℃）内基本完成松弛（9- 11）。为了使CRS对钙的结合与其假定的肌肉松弛的生理作用相一致，在这段时间内，钙的结合量必须足够大。
MCCOLLUM, WILLIAM B., HR BESCH, JR., MARK L. ENTMAN, AND ARNOLD SCHWARTZ. Apparent initial binding rate of calcium by canine cardiac-relaxing system. Am. J. Physiol. 223 (3): 608-614. 1972-A stopped-flow spectrophotometric method was employed to measure initial calcium-binding rates (presteady state) by a vesicular fraction from canine cardiac tissue. The vesicles probably represent elements of sarcoplasmic reticulum and, hence, are involved in muscle relaxation. The procedure for isolation of the relaxing system was refined so that the preparation bound 60-90 nmoles of calcium(dependent on ATP) per milligram protein at 25 C. Fresh preparations bound a minimum of 130 pmoles calcium per milligram protein per millisecond. The amount of binding in 200 msec was 15.5 nmoles/mg protein or approximately 100 nmoles calcium per gram wet weight cardiac muscle at 37 C. The binding capacity and the rate of calcium binding are consistent with the postulated role of this vesicular fraction in cardiac muscle relaxation. stopped-flow; murexide; sarcoplasmic reticulum; relaxationTHE PROBABLE central role of the cardiac sarcoplasmic reticulum(SR) in active relaxation of functioning myocardium is now well established (1, 3-6, 11, 17, 18, 22). The relaxing system (CRS), l consisting of vesicles derived mainly from the cardiac sarcoplasmic reticulum, has the capacity to bind calcium in an amount necessary to effect relaxation of fully activated fibers (4, 5, 9, 18, 22). Relaxation is essentially complete in approximately 200 msec (at 25 C) in canine myocardium in vivo (9-l 1). For calcium binding by CRS to be consistent with its presumed physiological role of muscle relaxation, the amount of binding must be of sufficient magnitude within this period of time.