Bovine plasma amine oxidase (PAO) oxidizes substrate by a proton activation mechanism

Conference · Thu May 01 04:00:00 EDT 1986 · Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States)

OSTI ID:5272237

Hartmann, C; Klinman, J P

PAO catalyzes the oxidative deamination of amines to aldehydes, concomitant with a 2e/sup -/ reduction of O/sub 2/ to H/sub 2/O/sub 2/. Several investigators have proposed recently that the organic cofactor in PAO is pyrroloquinoline quinone (PQQ), hitherto seen exclusively in prokaryotes. The structure and properties of PQQ predict first, that substrate and PAO will form a covalent adduct and second, that substrate will be oxidized via proton abstraction. In earlier studies from this laboratory, steady state isotope effects, in conjunction with an intrinsic isotope effect, have been shown to provide microscopic rate constants from complex mechanisms. In this study, V, D/sub V/, V/K and /sup D/(V/K) have been measured for the oxidation of a series of nine ring-substituted benzylamines and (1-/sup 2/H/sub 2/)-benzylamines with PAO. The series of substrates was chosen to minimize collinearity in the electronic and hydrophobic properties of ring substituents. Computed rate constants for the C-H bond cleavage step indicate a strong correlation with electron withdrawing substituents, rho = 1.3, confirming the formation of a discrete carbanion intermediate upon substrate activation. Additional studies are in progress, with the objective of trapping and characterizing the putative adduct between PAO and substrates.

• Research Organization: Univ. of California, Berkeley
• OSTI ID: 5272237
• Report Number(s): CONF-8606151-
• Conference Information: Journal Name: Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States) Journal Volume: 45:6
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ALDEHYDES
AMINES
ANIMALS
BARYONS
BIOLOGICAL MATERIALS
BLOOD
BLOOD PLASMA
BODY FLUIDS
CATTLE
CHEMICAL REACTIONS
DEAMINATION
DEUTERIUM
DOMESTIC ANIMALS
ELECTRONS
ELEMENTARY PARTICLES
ENZYME ACTIVITY
ENZYMES
FERMIONS
HADRONS
HYDROGEN ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LEPTONS
LIGHT NUCLEI
MAMMALS
MATERIALS
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PROTONS
RUMINANTS
STABLE ISOTOPES
SUBSTRATES
TRACER TECHNIQUES
VERTEBRATES