底物会干扰外膜磷脂酶A的二聚化。

Substrate interferes with dimerisation of outer membrane phospholipase A.

作者信息

Kingma Roelie L, Egmond Maarten R

机构信息

Department of Membrane Enzymology, Centre for Biomembranes and Lipid Enzymology, Institute of Biomembranes, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.

出版信息

FEBS Lett. 2002 Apr 10;516(1-3):31-4. doi: 10.1016/s0014-5793(02)02461-4.

DOI:10.1016/s0014-5793(02)02461-4

PMID:11959097

Abstract

Outer membrane phospholipase A (OMPLA) activity is regulated by reversible dimerisation with the dimer being the active species. Observed lag phases in activity indicated that dimerisation may be slow relative to turnover. A covalent OMPLA dimer indeed did not display lag phase behaviour. A model for OMPLA kinetics was proposed accounting for a slow dimerisation step. Preincubation conditions determined the initial amount of monomer and influenced both lag times and final activities. Under the conditions used, substrate concentrations higher than 50 mol% inhibited OMPLA activity and increased lag times. Our results may shed more light on mechanisms controlling OMPLA activity in vivo.

摘要

外膜磷脂酶A（OMPLA）的活性通过与二聚体可逆二聚化来调节，二聚体是活性形式。观察到的活性延迟阶段表明，相对于周转而言，二聚化可能较慢。共价OMPLA二聚体确实没有表现出延迟阶段行为。提出了一个OMPLA动力学模型，该模型考虑了缓慢的二聚化步骤。预孵育条件决定了单体的初始量，并影响延迟时间和最终活性。在所使用的条件下，高于50 mol%的底物浓度会抑制OMPLA活性并延长延迟时间。我们的结果可能会更清楚地揭示体内控制OMPLA活性的机制。