Stereochemistry of the hydrolysis reaction catalyzed by endoglucanase Z from Erwinia chrysanthemi

FEBS Letters

Henrissat, B.²  Bauzan, M.¹  Barras, F.¹  Bortoli-German, I.¹  Heyraud, A.²  Gey, C.²  Rouvier, J.¹ 

[1] Laboratoire de Chimie Bactérienne, CNRS, 31 Chemin Joseph Aiguier, BP 71, F-13277 Marseille cedex 9, France;Centre de Recherches sur les Macromolécules Végétales, CNRS, BP 53, F-38041 Grenoble, France

关键词: Cellulase;    Endoglucanase;    Reaction mechanism;    Hydrolysis;    Erwinia chrysanthemi;   

DOI  :  10.1016/0014-5793(92)80183-H

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Endoglucanase Z from the phytopathogenic bacterium Erwinia chrysanthemi (strain 3937) was purified by affinity chromatography on microcrystalline cellulose Avicel PH101. A kinetic characterization using p-nitrophenyl β-d-cellobioside and p-nitrophenyl β-d-lactoside as substrates was conducted: endoglucanase Z exhibited K _m values of 3 mM and 7.5 mM and V _m values of 129 and 40 nmol·min⁻¹·mg⁻¹ towards p-nitrophenyl β-d-cellobioside (k _cat=0.1 s⁻¹) and p-nitrophenyl β-d-lactoside (k _cat=0.03 s⁻¹), respectively). The hydrolysis of cellotetraitol by endoglucanase Z was followed by HPLC and ¹H NMR. Results show that cellobiitol and β-cellobiose are initially formed, demonstrating that the enzyme is acting by a molecular mechanism retaining the anomeric configuration. This suggests the involvement of a glycosyl-enzyme intermediate.

【 授权许可】

Unknown