Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
, 467 (1), 95-106

Pre-steady State Kinetic Characterization of Human Peroxiredoxin 5: Taking Advantage of Trp84 Fluorescence Increase Upon Oxidation

Affiliations

Pre-steady State Kinetic Characterization of Human Peroxiredoxin 5: Taking Advantage of Trp84 Fluorescence Increase Upon Oxidation

Madia Trujillo et al. Arch Biochem Biophys.

Abstract

Human peroxiredoxin 5 (PRDX5) catalyzes different peroxides reduction by enzymatic substitution mechanisms. Enzyme oxidation caused an increase in Trp84 fluorescence, allowing performing pre-steady state kinetic measurements. The technique was validated by comparing with data available from the literature or obtained herein by alternative approaches. PRDX5 reacted with organic hydroperoxides with rate constants in the 10(6)-10(7)M(-1)s(-1) range, similar to peroxynitrite-mediated PRDX5 oxidation, whereas its reaction with hydrogen peroxide was slower (10(5)M(-1)s(-1)). The method allowed determining the kinetics of intramolecular disulfide formation as well as thioredoxin 2-mediated reduction. The reactivities of PRDXs with peroxides were surprisingly high considering thiol pK(a), indicating that other protein determinants are involved in PRDXs specialization. The order of reactivities between PRDX5 towards oxidizing substrates differ from other PRDXs studied, pointing to a selective action of PRDXs with respect to peroxide detoxification, helping to rationalize the multiple enzyme isoforms present even in the same cellular compartment.

Similar articles

See all similar articles

Cited by 41 articles

See all "Cited by" articles

Publication types

LinkOut - more resources

Feedback