Substrate isomerization inhibits ribulosebisphospate carboxylase‐oxygenase during catalysis

FEBS Letters

Edmondson, Daryl L.¹  Kane, Heather J.¹  Andrews, T.John¹ 

[1] Research School of Biological Sciences, Australian National University, PO Box 475, Canberra, ACT 2601, Australia

关键词: Ribulosebisphosphate carboxylase-oxygenase;    Ribulose 1;    5-bisphosphate carboxylase-oxigenase;    D-;    Enzyme mechanism;    Enzyme inhibition;    Xylulose 1;    5-bisphosphate;    D-;    Photosynthesis;    ribulose-P2;    D-ribulose 1;    5-bisphosphate;    xylulose-P2;    D-xylulose 1;    5-bisphosphate;    3-ketoarabinitol-P2;    3-keto-D-arabinitol 1;    5-bisphosphate;    carboxyarabinitol-1-P;    2'-carboxy-D-arabinitol 1-phosphate;    Rubisco;    ribulose-P2 carboxylase-oxygenase;    glycerol-P;    glycerol-3-phosphate;   

DOI  :  10.1016/0014-5793(90)80066-R

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The inhibition of purified spinach ribulosebisphosphate carboxylase-oxygenase which occurs progressively during catalysis in vitro is caused by accumulation of at least two tight-binding inhibitors at the catalytic site. Reduction of these inhibitors with NaB³H₄, followed by dephosphorylation, produced a mixture of xylitol and arabinitol, thus identifying one of them as D-xylulose 1,5-bisphosphate. It was formed during carboxylation, presumably by a stereochemically incorrect reprotonation of the 2,3-enediolate intermediate bound at the catalytic site. Under the conditions used, this epimerization occurred approximately once for every 400 carboxylation turnovers. Another inhibitor may be 3-keto-D-arabinitol 1,5-bisphosphate which would also be formed by misprotonation of the enediolate intermediate, but at C-2 rather than at C-3.

【 授权许可】

Unknown