Ultrasensitive glycogen synthesis in Cyanobacteria

FEBS Letters

Gómez Casati, Diego F¹  Iglesias, Alberto A¹  Aon, Miguel A¹ 

[1] Instituto Tecnológico de Chascomús (INTECH-CONICET). Camino Circunv. Laguna km 6, CC 164, 7130 Chascomús, Argentina

关键词: ADPglucose pyrophosphorylase;    Glycogen and starch biosynthesis;    Enzyme regulation;    Molecular crowding;    Anabaena PCC 7120;    ADPGlc;    ADPglucose;    AGPase;    ADPglucose pyrophosphorylase;    PEG;    polyethyleneglycol;    3PGA;    3-phosphoglycerate;   

DOI  :  10.1016/S0014-5793(99)00201-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Cyanobacter ADPglucose pyrophosphorylase exhibits a ultrasensitive response in activity towards its allosteric effector 3-phosphoglycerate, elicited by orthophosphate and polyethyleneglycol-induced molecular crowding. The ultrasensitive response was observed either when the enzyme operates in the zero or first order region for its physiological substrates. The ultrasensitivity exhibited maximal amplification factors of 15–19-fold with respect to 1% of the maximal system velocity. Only a 2.4–3.8-fold increase in 3PGA concentration was necessary to augment the flux from 10% to 90% through AGPase as compared with 200-fold required for the control. The results are discussed in terms of finely tuned regulatory mechanisms of polysaccharide synthesis in oxygenic photosynthetic organisms.

【 授权许可】

Unknown