Bovine plasma amine oxidase (PAO) oxidizes substrate by a proton activation mechanism
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-; TRN: 86-031448
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 45:6; Conference: 76. annual meeting of the Federation of American Society for Experimental Biology, Washington, DC, USA, 8 Jun 1986
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AMINES
DEAMINATION
OXIDOREDUCTASES
ENZYME ACTIVITY
ALDEHYDES
BLOOD PLASMA
CATTLE
DEUTERIUM
ELECTRONS
PROTONS
SUBSTRATES
TRACER TECHNIQUES
ANIMALS
BARYONS
BIOLOGICAL MATERIALS
BLOOD
BODY FLUIDS
CHEMICAL REACTIONS
DOMESTIC ANIMALS
ELEMENTARY PARTICLES
ENZYMES
FERMIONS
HADRONS
HYDROGEN ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LEPTONS
LIGHT NUCLEI
MAMMALS
MATERIALS
NUCLEI
NUCLEONS
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
RUMINANTS
STABLE ISOTOPES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques