STUDIES ON THE AMIDE AND C-TERMINAL RESIDUES IN PROTEINS .1. CHARACTERIZATION OF THE C-TERMINAL RESIDUE
STUDIES ON THE AMIDE AND C-TERMINAL RESIDUES IN PROTEINS .1. CHARACTERIZATION OF THE C-TERMINAL RESIDUE
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DOI：
10.1042/bj0680105
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发表时间：
1958-01-01
影响因子：
4.1
通讯作者：
REES, MW
中科院分区：
文献类型：
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作者：
CHIBNALL, AC;REES, MW
在初步酯化后，蛋白质中C-末端残基的羧基可以用硼氢化锂还原，并且在随后的酸水解中，改性的残基作为氨基醇或羟基氨基酸存在于水解产物中。对测定蛋白质中C-末端残基的方法的适用性进行了探索，与Crawhall和Elliott（1955）一致，发现该问题因在所选条件下发生的肽键同时还原裂解而变得复杂，其程度为总肽键的1-2%。数据显示，对于低分子量蛋白质，如胰岛素（5732），干扰不严重，可以对C-末端残基进行满意的测定。然而，对于分子量高得多的蛋白质，如β-乳球蛋白（37000），干扰是严重的。该方法不推荐作为蛋白质的可靠方法，但它可能用于低分子量的肽。
The carboxyl groups of C-terminal residues in proteins, after preliminary esterification, can be reduced with lithium borohydride, and on subsequent acid hydrolysis the modified residues are present in the hydrolysate as amino alcohols or hydroxyamino acids. The suitability of the procedure for determining the C-terminal residues in proteins was explored, and in agreement with Crawhall and Elliott (1955), it was found that the issue was complicated by the simultaneous reductive cleavage of peptide bonds which occurs, under the conditions chosen, to the extent of 1-2% of the total peptide bonds. Data are presented snowing that with a protein of low molecular weight such as insulin (5732) the interference is not serious and a satisfactory determination of the C-terminal residues can be made. With a protein of much higher molecular weight such as /3-lactoglobulin (37000), however, the interference is serious. The procedure is not recommended as a reliable one for proteins but it may be of use with peptides of low molecular weight.