Base‐catalyzed reactivation of glucogen phosphorylase reconstituted with a coenzyme‐substrate conjugate and its analogues

FEBS Letters

Horinishi, Nobutaka¹  Tagaya, Mitsuo¹  Fukui, Toshio¹ 

[1] Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567, Japan

关键词: Glycogen phosphorylase;    Coenzyme-substrate conjugate;    Pyridoxal 5′-phosphate;    Enzyme mechanism;    Glc-1-P;    α-D-glucose 1-phosphate;    PLP;    pyridoxal 5′-phosphate;    PLDP;    pyridoxal 5′-diphosphate;    PLDP-Glc;    -Gal;    -Man and -Xyl;    pyridoxal (5′) diphospho(1)-α-D-glucose;    -galactose;    -mannose and -xylose;    respectively;    PLP-;    PLDP-;    PLDP-Glc-;    PLDP-Gal-;    PLDP-Man- and PLDP-Xyl-enzymes;    enzymes reconstituted with the corresponding compounds;    HPLC;    high-performance liquid chromatography;   

DOI  :  10.1016/0014-5793(88)80864-0

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Glycogen phosphorylase reconstituted with pyridoxal (5′)diphospho(1)-α-D-glucose (PLDP-Glc) is catalytically inactive but slowly converted to the active enzyme through the cleavage of the pyrophosphate linkage. A similar reaction occurs more rapidly on PLDP-Gal and -Xyl but not on PLDP-Man. Values of pK _a for all the reactions are about 8.3, suggesting the participation of a common basic residue in these reactions. Based on the present and other results, it is presumed that Tyr-573 or Lys-574 acts as the base abstracting the proton from 2-hydroxyl group of the glucosyl moiety of PLDP-Glc.

【 授权许可】

Unknown