Kinetic and spectral properties of pea cytosolic ascorbate peroxidase

被引：44

作者：

Marquez, LA

Quitoriano, M

Zilinskas, BA

Dunford, HB

机构：

[1] UNIV ALBERTA,DEPT CHEM,EDMONTON,AB T6G 2G2,CANADA

[2] RUTGERS STATE UNIV,COOK COLL,DEPT PLANT SCI,NEW BRUNSWICK,NJ 08903

来源：

FEBS LETTERS | 1996年 / 389卷 / 02期

关键词：

compound I; compound II; transient state kinetics; optical spectra; Ascorbate oxidation; pH dependence; cytochrome c peroxidase; comparison;

D O I：

10.1016/0014-5793(96)00562-5

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Sufficient highly purified native pea cytosolic ascorbate peroxidase was obtained to characterize some of its kinetic and spectral properties, Its rate constant for compound I formation from reaction with H2O2 is 4.0 x 10(7) M(-1) s(-1), somewhat faster than is typical for peroxidases, Compound I has the typical optical spectrum of an iron(IV)-porphyrin-pi-cation radical, despite considerable homology with yeast cytochrome c peroxidase. The rate constant for compound I reduction by ascorbate is extremely fast (8.0 x 10(7) M(-1) s(-1) at pH 7.8), again in marked contrast to the behavior of the yeast enzyme, The pH-rate profile for compound I formation indicates a pK(a) value of 5.0 for a group affecting the active site reaction.

引用

页码：153 / 156

页数：4

共 21 条

[11]

MIYAKE C, 1993, PLANT CELL PHYSIOL, V34, P881

[12]

NAKANO Y, 1981, PLANT CELL PHYSL, V22, P880

[13] ENTHALPY OF DECOMPOSITION OF HYDROGEN-PEROXIDE BY CATALASE AT 25 DEGREES C (WITH MOLAR EXTINCTION COEFFICIENTS OF H2O2 SOLUTIONS IN UV) [J].