Enhancement of carbonic anhydrase activity by erythrocyte membranes.
Enhancement of carbonic anhydrase activity by erythrocyte membranes.
复制标题
红细胞膜增强碳酸酐酶活性。
DOI：
10.1016/0003-9861(89)90392-5
复制
发表时间：
1989
影响因子：
3.9
通讯作者：
Coleman,PS
中科院分区：
文献类型：
--
作者：
Parkes,JL;Coleman,PS
人红细胞膜是红细胞碳酸酐酶高（CA II）和低（CA I）活性同工酶的有效增强剂。膜的存在使牛CA II、人CA II和人CA的co2水合作用分别增加1.6倍、3.5倍和11.6倍。高活性CA同工酶在1 ~ 3 μg /ml膜蛋白存在时刺激最大。在无膜和有膜条件下，牛CAⅱ（4 nm）的vmax从0.302增加到0.839 mm/s，人CAⅱ（6 nm）的vmax从0.113增加到0.414 mm/s。对于牛CA II，二氧化碳的表观km从13.2 mm增加到51.2 mm，对于人CA II，从6.5 mm增加到38.5 mm。经线性蔗糖密度梯度离心后，膜加酶混合物仅在含膜梯度组分中表现出Ca活性增强，验证了膜对酶活性的刺激能力，表明复合物形成紧密而稳定。CA活性的膜增强似乎是一种普遍现象，小鼠肝细胞膜也刺激CA活性，尽管不如红细胞膜有效。在许多可溶的推定效应物中，只有咪唑能提高CA II活性，其程度与红细胞膜相当；然而，咪唑并没有刺激人类CA i的活性，数据与CA II通过膜结合激活的模型一致，这种模型可能会影响酶构象的扭曲，从而促进膜结合和酶结合的质子穿梭残基（可能是组氨酸的咪唑部分）和酶催化位点的锌结合氢氧化物之间的分子内和/或分子间质子转移。
The human erythrocyte membrane is an efficient enhancer of both high (CA II) and low (CA I) activity isozymes of red blood cell carbonic anhydrase. The presence of membrane increased CO2hydration catalyzed by bovine CA II 1.6-fold, human CA II 3.5-fold, and human CA 11.6-fold. With the high activity CA isozymes, maximal stimulation was observed in the presence of 1–3 μg membrane protein/ml. TheVmaxfor bovine CA II (4 nm) rose from 0.302 to 0.839 mm/s, while that for human CA II (6 nm) increased from 0.113 to 0.414 mm/s in the absence and presence of membrane, respectively. The apparentKmfor CO2increased from 13.2 to 51.2 mmfor bovine CA II, and from 6.5 to 38.5 mmfor human CA II. Mixtures of membrane plus enzyme, upon centrifugation through linear sucrose density gradients, displayed enhanced Ca activity only in membrane-containing gradient fractions, verifying the stimulatory ability of membranes on enzyme activity and indicating tight and stable complex formation. Membrane enhancement of CA activity appears to be a general phenomenon in that mouse hepatocyte membranes also stimulated CA activity, although less efficiently than erythrocyte membranes. Of the many soluble putative effectors assayed, only imidazole enhanced CA II activity to an extent comparable with erythrocyte membranes; imidazole did not, however, stimulate the activity of human CA I. The data are consistent with a model of CA II activation by membrane association that may effect a distortion of the enzyme conformation in such a way as to facilitate intra- and/or intermolecular proton transfer between membrane-bound and enzyme-bound proton shuttling residues (perhaps the imidazole moiety of histidine) and the Zn-bound hydroxide at the catalytic site of the enzyme.
登录
查看更多内容
影响因子：
5.2
作者：
Y. Pocker;T. Deits
通讯作者：
T. Deits
向动物注射醛固酮后，刺激钠通过离体蟾蜍膀胱的主动转运。
影响因子：
4.8
作者：
Jean Crabbé
通讯作者：
Jean Crabbé
血红蛋白和碳酸酐酶活性位点之间的质子转移。
DOI：
10.1016/s0021-9258(17)40858-1
发表时间：
1978
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
D. Silverman;C. Tu;G. Wynns
通讯作者：
G. Wynns
碳酸酐酶同工酶a的动力学和机制
影响因子：
5.2
作者：
S. Lindskog;Paul Engberg;C. Forsman;S. Ibrahim;B. Jonsson;I. Simonsson;L. Tibell
通讯作者：
L. Tibell
脑中可溶性膜结合碳酸酐酶的表征和生物合成
影响因子：
4.7
作者：
V. Sapirstein;P. Strocchi;M. Wesołowski;J. M. Gilbert
通讯作者：
J. M. Gilbert