Taketa F, Mauk A G, Mauk M R, Brimhall B
J Mol Evol. 1977 May 13;9(3):261-71. doi: 10.1007/BF01796114.
The tryptic peptides from the betaA and betaB chains of cat hemoglobins A and B have isolated and the amino acid compositions determined. Differences between the two chains were found in two peptides, betaT-1 (Glylead toSer) and betaT-14 (Asnlead toSer and Lyslead toArg). The Glylead toSer and Lysleand toArg substitutions areplaced at beta-1 and beta-144 respectively from earlier work, and the third substitution, AsnleadSer at beta-139 is suggested from this work. in addition, the presence of a blocked amino terminus in betaB has been confirmed. Tentative sequences constructed by homology with known beta-chain structures suggest the occurrence of substitutions at alpha1beta1 contacts in betaA and betaB that may be functionally significant. There are at least 18 differences in amino acid composition between cat betaA and dog beta-chains and 22 differences between cat betaA and normal adult human beta-chains.
已分离出猫血红蛋白A和B的βA链和βB链的胰蛋白酶肽段，并测定了氨基酸组成。在两个肽段βT - 1（甘氨酸突变为丝氨酸）和βT - 14（天冬酰胺突变为丝氨酸和赖氨酸突变为精氨酸）中发现了两条链之间的差异。根据早期研究，甘氨酸突变为丝氨酸和赖氨酸突变为精氨酸的替换分别位于β - 1和β - 144处，而本研究表明在β - 139处存在天冬酰胺突变为丝氨酸的第三次替换。此外，已证实βB中存在封闭的氨基末端。通过与已知β链结构的同源性构建的初步序列表明，βA和βB中α1β1接触处发生了替换，这可能具有功能意义。猫βA链与狗β链之间的氨基酸组成至少有18处差异，猫βA链与正常成人人类β链之间有22处差异。
