Source: Bovine Plasma

I.U.B.: 1.4.3.6

Plasma amine oxidase (PAO) catalyzes the reaction:

RCH₂NH₂ + O₂ + H₂O → RCHO + NH₃ + H₂O₂

Bovine plasma amine oxidase has a molecular weight of 170 kDa and an optimum pH of 6.2 for spermine and 7.2 for spermidine. Amine oxidases are divided into two classes: the pyridoxal and copper containing enzyme to which plasma amine oxidase belongs, and the FAD-containing amino oxidases. Natural substrates include catecholamines, tryptamine derivatives and other physiologically active amines. Plasma amine oxidase is used in research requiring nitrogen group transfers. The molecule is composed of two identical polypeptide chains. There are two pyridoxal phosphates and two atoms of Cu⁺ per molecule. Bovine plasma amine oxidase is inhibited by copper chelating agents, many carboxyl reagents such as cuprizone, hydroxylamine and cyanide. Benzoic acid and benzyl alcohol are both non-competitive inhibitors (K_I = 30 and 34mM respectively). The assay for determination of amine oxidases employed at Worthington is essentially that of Tabor et al., JBC, 208, 645, (1954) with the reaction temperature reduced to 25°C.