柠檬叶片中鸟氨酸氨甲酰基转移酶的部分纯化及性质

Partial purification and properties of ornithine carbamoyltransferase from Citrus limonum leaves.

作者信息

Bellocco E, Leuzzi U, De Gregorio A, Laganà G, Risitano A, Desideri A, Cuzzocrea G

机构信息

Department of Organic and Biological Chemistry, University of Messina Salita Sperone.

出版信息

Biochem Mol Biol Int. 1993 Feb;29(2):281-9.

PMID:8495212

Abstract

Ornithine carbamoyltransferase (carbamoylphosphate: L-ornithine carbamoyltransferase, EC 2.1.3.3) has been partially purified from C.limonum leaves. The data indicate the presence of only the anabolic enzyme. The activity is strongly influenced by pH, ionic strength and ornithine concentration. Optimal activity for the enzyme dissolved in the tri-buffer: diethanolamine,2-(N-morpholino) ethanesulfonic acid, N-ethylenmorpholine (0.051 M/0.1 M/0.051 M) is at pH 9.0, when ornithine is 10 mM. The enzyme catalyses an ordered-sequential process in which carbamoyl phosphate binds first followed by L-ornithine and then L-citrulline leaves followed by phosphate. Support for this statement comes from product inhibition and evidence of abortive ternary complex formation.

摘要

鸟氨酸氨甲酰转移酶（氨甲酰磷酸：L-鸟氨酸氨甲酰转移酶，EC 2.1.3.3）已从柠檬叶中部分纯化。数据表明仅存在合成代谢酶。该活性受pH、离子强度和鸟氨酸浓度的强烈影响。溶解在三缓冲液（二乙醇胺、2-（N-吗啉代）乙磺酸、N-乙基吗啉，0.051 M/0.1 M/0.051 M）中的酶，在鸟氨酸为10 mM时，最佳活性在pH 9.0。该酶催化一个有序的顺序过程，其中氨甲酰磷酸首先结合，随后是L-鸟氨酸，然后L-瓜氨酸离开，接着是磷酸。这一说法的依据来自产物抑制和无效三元复合物形成的证据。