马生长激素中组氨酸残基的乙氧基甲酰化

Ethoxyformylation of histidine residues in equine growth hormone.

作者信息

Fukushima J G, Cascone O, Santomé J A, Biscoglio de Jimenez Bonino M J

机构信息

Institute of Biochemistry and Bio-Physicochemistry (UBA-CONICET), Faculty of Pharmacy and Biochemistry, Buenos Aires, Argentina.

出版信息

Int J Pept Protein Res. 1987 Sep;30(3):365-70. doi: 10.1111/j.1399-3011.1987.tb03343.x.

DOI:10.1111/j.1399-3011.1987.tb03343.x

PMID:3692683

Abstract

Reactivity of histidine residues in equine growth hormone to ethoxyformic anhydride was studied. The existence of two kinetically different sets was demonstrated: one of them including only the slow reacting histidine 169 (k = 0.164 min-1) and the other containing fast reacting histidines 19 and 21 (k = 0.892 min-1). A correlation between the decrease in the capacity to compete with 125I-labeled hormone for rat liver binding sites and the degree of ethoxyformylation of the fast group was found. Circular dichroism studies indicated no significant conformational changes in the protein with all three residues modified. These results fully agree with those obtained for bovine growth hormone which is further evidence supporting the vinculation of histidines 19 and/or 21 with the binding site of these hormones to their specific receptors.

摘要

研究了马生长激素中组氨酸残基对乙氧基甲酸酐的反应活性。结果表明存在两组动力学不同的组氨酸：一组仅包含反应缓慢的组氨酸169（k = 0.164 min⁻¹），另一组包含反应快速的组氨酸19和21（k = 0.892 min⁻¹）。发现与¹²⁵I标记的激素竞争大鼠肝脏结合位点的能力下降与快速反应组的乙氧基甲酰化程度之间存在相关性。圆二色性研究表明，当所有三个残基都被修饰时，蛋白质没有明显的构象变化。这些结果与牛生长激素的结果完全一致，这进一步证明了组氨酸19和/或21与这些激素与其特异性受体的结合位点之间的联系。