Bennett H P, Elliott D F, Evans B E, Lowry P J, McMartin C
Biochem J. 1972 Sep;129(3):695-701. doi: 10.1042/bj1290695.
Incubation with a mixture of Sepharose-bound peptidases was shown to result in the quantitative release of amino acids from certain peptides and S-aminoethylated proteins. Subtraction of the low background values of amino acids generated by the enzymes enables amino acid ratios of corticotrophin-(1-24)-tetracosapeptide to be determined with a standard deviation on repeat digestions of 3-5%. Good values were obtained for amino acids that are completely or partially destroyed on acid hydrolysis, i.e. tryptophan, tyrosine, serine, asparagine and glutamine. Experiments with peptides containing d-amino acids showed that the enzyme mixture is stereospecific and could therefore be used to detect the presence of d-residues in peptides. The enzyme mixture completely hydrolyses peptide fragments obtained after Edman degradation and should therefore be useful for determining sequences of peptides containing acid-labile amino acid residues. The activities of the bound enzymes were unaltered over a period of 7 months and they provide a simple, reproducible procedure for the quantitative determination of amino acids in peptides and proteins containing l-amino acids.
与琼脂糖结合的肽酶混合物温育后，结果显示某些肽和S-氨乙基化蛋白质中的氨基酸会被定量释放。减去酶产生的低背景氨基酸值后，促肾上腺皮质激素（1 - 24）-二十四肽的氨基酸比例在重复消化时的标准偏差为3 - 5%，仍可测定。对于在酸水解时会完全或部分被破坏的氨基酸，即色氨酸、酪氨酸、丝氨酸、天冬酰胺和谷氨酰胺，也能得到较好的值。含有d-氨基酸的肽的实验表明，该酶混合物具有立体特异性，因此可用于检测肽中d-残基的存在。该酶混合物能完全水解埃德曼降解后得到的肽片段，因此对于确定含有酸不稳定氨基酸残基的肽的序列应是有用的。结合酶的活性在7个月内未发生改变，它们为定量测定含l-氨基酸的肽和蛋白质中的氨基酸提供了一种简单、可重复的方法。
