Improvement of Peroxygenase Activity by Relocation of a Catalytic Histidine within the Active Site of Horseradish Peroxidase

Biochemistry ◽  
1998 ◽  
Vol 37 (30) ◽  
pp. 10828-10836 ◽  
Author(s):  
Marina I. Savenkova ◽  
Jane M. Kuo ◽  
Paul R. Ortiz de Montellano
Keyword(s):  
Horseradish Peroxidase ◽  
Active Site

Kinetics of the oxidation of reduced nicotinamide adenine dinucleotide by horseradish peroxidase compounds I and II

1986 ◽  
Vol 64 (4) ◽  
pp. 323-327 ◽  
Author(s):  
Mohammed A. Kashem ◽  
H. Brian Dunford
Keyword(s):  
Horseradish Peroxidase ◽  
Active Site ◽  
Nicotinamide Adenine Dinucleotide ◽  
Ph Dependence ◽  
Transient State ◽  
Nicotinamide Adenine ◽  
Compound I ◽  
Single Ionization ◽  
Reduced Nicotinamide Adenine Dinucleotide ◽  
Kinetics Of

The transient state kinetics of the oxidation of reduced nicotinamide adenine dinucleotide (NADH) by horseradish peroxidase compound I and II (HRP-I and HRP-II) was investigated as a function of pH at 25.0 °C in aqueous solutions of ionic strength 0.11 using both a stopped-flow apparatus and a conventional spectrophotometer. In agreement with studies using many other substrates, the pH dependence of the HRP-I–NADH reaction can be explained in terms of a single ionization of pKa = 4.7 ± 0.5 at the active site of HRP-I. Contrary to studies with other substrates, the pH dependence of the HRP-H–NADH reaction can be interpreted in terms of a single ionization with pKa of 4.2 ± 1.4 at the active site of HRP-II. An apparent reversibility of the HRP-II–NADH reaction was observed. Over the pH range of 4–10 the rate constant for the reaction of HRP-I with NADH varied from 2.6 × 105 to5.6 × 102 M−1 s−1 and of HRP-II with NADH varied from 4.4 × 104 to 4.1 M−1 s−1. These rate constants must be taken into consideration to explain quantitatively the oxidase reaction of horseradish peroxidase with NADH.

Characterisation of a haem active-site mutant of horseradish peroxidase, Phe41 Val, with altered reactivity towards hydrogen peroxide and reducing substrates

1992 ◽  
Vol 207 (2) ◽  
pp. 507-519 ◽  
Author(s):  
Andrew T. SMITH ◽  
Stephen A. SANDERS ◽  
Roger N. F. THORNELEY ◽  
Julian F. BURKE ◽  
Robert R. C. BRAY
Keyword(s):  
Hydrogen Peroxide ◽  
Horseradish Peroxidase ◽  
Active Site
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