Bossa F, Barra D, Martini F, Schirch L V, Fasella P
Eur J Biochem. 1976 Nov 15;70(2):397-401. doi: 10.1111/j.1432-1033.1976.tb11029.x.
The amino acid sequence of the coenzyme-binding site of serine transhydroxymethylase from rabbit liver has been determined. After reduction with NaBH4 and aminoethylation, a first sample of enzyme was digested with thermolysin and a single phosphopyridoxyl peptide was isolated. A second sample of similarly treated enzyme was digested with chymotrypsin and three phosphopyridoxyl peptides clearly originating from a unique coenzyme-binding site were isolated. Sequence analysis of these peptides indicate the following structure: Val-Val-Thr-Thr-His(Pxy)-Thr-Leu. Sequence homologies of the active site of various pyridoxalphosphate enzymes are discussed in terms of a possible catalytic role and of evolution of this class of proteins.
已确定兔肝脏丝氨酸转羟甲基酶辅酶结合位点的氨基酸序列。用NaBH₄还原并氨乙基化后，取第一份酶样品用嗜热菌蛋白酶消化，分离出一个磷酸吡哆醛肽。取第二份经同样处理的酶样品用胰凝乳蛋白酶消化，分离出三个明显源自独特辅酶结合位点的磷酸吡哆醛肽。这些肽的序列分析表明具有以下结构：缬氨酸-缬氨酸-苏氨酸-苏氨酸-组氨酸（磷酸吡哆醛）-苏氨酸-亮氨酸。根据这类蛋白质可能的催化作用和进化，讨论了各种磷酸吡哆醛酶活性位点的序列同源性。
