Interaction of mannose‐6‐phosphate with the hysteretic transition in glucose‐6‐phosphate hydrolysis in intact liver microsomes

FEBS Letters

Vidal, Hubert²  Larue, Marie-Josée²  St-Denis, Jean-François¹  Berteloot, Alfred³  van de Werve, Gérald² 

[1] Laboratoire d'Endocrinology Métabolique, Department of Biochemistry, University of Montreal, Que. 113C 3J7, Canada;Laboratoire d'Endocrinology Métabolique, Department of Nutrition University of Montreal, Que. 113C 3J7, Canada;Laboratoire d'Endocrinology Métabolique, Department of Groupe de Recherche en Transport Membranaire University of Montreal, Que. 113C 3J7, Canada

关键词: Liver;    Glucose-6-phosphatase;    Microsome;    Hysteresis;    Mannose-6-phosphate;   

DOI  :  10.1016/0014-5793(92)80439-N

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We showed previously that glucose-6-phosphatase activity was characterised in intact liver microsomes by a hysteretic transition between a rapid and a slower catalytic form of the enzyme. We have now further investigated the substrate specificity of these two kinetic forms. It was found that the pre-incubation of intact microsomes with mannose-6-phosphate or glucose-6-phosphate (50 μM for 30 s) suppressed the burst in glucose-6-phosphatase activity, that the hysteretic transition was reversible and that mannose-6-phosphate inhibited glucose-6-phosphate hydrolysis during the first seconds of incubation, but not anymore after the burst. Our results indicate (i) that mannose-6-phosphate is recognised by the enzyme and can promote the hysteretic transition and (ii) that the transient phase is part of the catalytic mechanism itself.

【 授权许可】

Unknown