Jiao J A, Podestá F E, Chollet R, O'Leary M H, Andreo C S
Department of Biochemistry, University of Nebraska-Lincoln 68583-0718.
Biochim Biophys Acta. 1990 Dec 5;1041(3):291-5. doi: 10.1016/0167-4838(90)90287-p.
An active-site peptide from maize (Zea mays L.) phosphoenolpyruvate carboxylase has been isolated, sequenced and identified in the primary structure following chemical modification/inactivation of the enzyme by pyridoxal 5'-phosphate and reduction with sodium borohydride. The amino acid sequence of the purified dodecapeptide is Val-Gly-Tyr-Ser-Asp-Ser-Gly-L*ys-Asp-Ala-Gly-Arg, which corresponds exactly to residues 599-610 in the deduced primary sequence of the maize-leaf enzyme. Comparative analysis of the deduced amino acid sequences of the enzyme from Escherichia coli, Anacystis nidulans and C3, C4 and Crassulacean acid metabolism plants indicates that they all contain this specific lysyl group, as well as a high degree of sequence homology flanking this species-invariant residue. This observation suggests a critical role for Lys-606 during catalysis by maize phosphoenolpyruvate carboxylase. This represents the first identification of a specific, species-invariant active-site residue in the enzyme.
一种来自玉米（Zea mays L.）磷酸烯醇式丙酮酸羧化酶的活性位点肽已被分离、测序，并在通过5'-磷酸吡哆醛对该酶进行化学修饰/失活并用硼氢化钠还原后，在一级结构中得到鉴定。纯化的十二肽的氨基酸序列为Val-Gly-Tyr-Ser-Asp-Ser-Gly-Lys-Asp-Ala-Gly-Arg，这与玉米叶片酶推导的一级序列中的599-610位残基完全对应。对大肠杆菌、集胞藻以及C3、C4和景天酸代谢植物中该酶推导的氨基酸序列进行比较分析表明，它们都含有这个特定的赖氨酰基团，以及在这个物种不变残基两侧的高度序列同源性。这一观察结果表明，Lys-606在玉米磷酸烯醇式丙酮酸羧化酶催化过程中起关键作用。这是该酶中首个特定的、物种不变的活性位点残基的鉴定。
