ISSN:
1432-1327
Keywords:
Keywords Copper amine oxidase
;
Trihydroxyphenylalanine quinone
;
Hydrazine inhibitors
;
Cobalt-substituted amine oxidase
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Abstract Bovine serum amine oxidase (BSAO) reacts with 2-hydrazinopyridine, which binds the organic cofactor 2,4,5-trihydroxyphenylalanine quinone, forming a band at 435 nm. The band shifts to 526 nm around 60 °C, to 415 nm upon denaturation, but only shifts to 429 nm upon Cu2+ depletion. Its wavelength and intensity suggest that the adduct has the azo conformation, whilst the same adduct of crystallineEscherichia coli amine oxidase (ECAO) shows the hydrazone conformation in the X-ray structure. The steady state kinetics of aminomethyl- and aminoethylpyridines confirm that the formation of the product Schiff base, analogous to the azo form of the 2-hydrazinopyridine adduct, is not hindered in solution. The structural stability of the adduct in the absence of Cu2+ is taken to imply hydrogen bonding of the pyridyl nitrogen to a conserved aspartate, as in the ECAO adduct. Thus the ECAO adduct provides a good model for a transient intermediate leading to formation of the BSAO azo adduct. On the basis of this model and of the catalytic competence of Co2+-substituted BSAO, confirmed by the present data, a catalytic reaction scheme is proposed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s007750050321
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