1. The purification of monoamine oxidase and diamine oxidase from normal human term placental tissue is described. 2. The properties of these enzymes are reported and compared with the properties of unpurified human pregnancy plasma. 3. This comparison shows that the amine oxidase of pregnancy plasma has properties corresponding to purified placental diamine oxidase, suggesting a placental orig...

Introduction Ascorbic acid oxidase (AAO) is ;I blue multi-copper oxidase that catalyses the four-electron reduction of dioxygen to water with concomitant one-electron oxidation of tlie reducing organic substrate [ 1 1. Copper-dependent A A O is found only in higher plants 12 I. The enzyme from Cucurbitu pep0 medullosa (green zucchini) is ;I dimer of 14OOOO-M,. containing eight copper ions of th...

Oxidation of the biologically important polyamines spermine and spermidine by plasma amine oxidase (PAO) was specified many years ago to occur at the terminal primary rather than internal secondary amine positions. However, the finding of sequential enzymatic conversion of spermine to spermidine and then to putrescine (1, 4-butanediamine) is superficially suggestive of metabolism at the seconda...

A procedure for obtaining crystalline preparations of the amine oxidase of Aspergillus niger has been developed. The method involved fractionations with ammonium sulfate and separation on successive columns of DEAE-cellulose, DEAE-sephadex and hydroxyl apatite. Crystals were formed when solid ammonium sulfate was added to solutions of the purified enzyme (of about 300to 350-times the specific a...

There was an increase in copper content proportional to the increase in specific activity of the enzyme during the purification of amine oxidase of Aspergillus niger. The recrystal lized enzyme preparation contained 1 g atom of copper per 83,000g of protein. This in dicated that the enzyme contained 3g atoms of copper per mole of enzyme. The copper in the enzyme was removed by dialysis against ...

Eidelberg, E., Baxter, C. F., Roberts, E. & Saldias, C. A. (1960) in Inhibition in the Nervous System and y-Aminobutyric Acid (Roberts, E., Baxter, C. F., Van Harreveld, A., Wiersma, C. A. G., Adey, W. R. & Killam, K. F., eds.), pp. 562-578, Pergamon Press, New York Fletcher, A. & Fowler, L. J. (1980) Biochem. Pharmacol. 29,145& 1459 Fletcher, A. & Fowler, L. J. (1982) J. Neurochem. 38, 1022-10...

Diamine oxidase Enzymes which oxidize diamines occur sporadically throughout the plant kingdom (Smith, 1980, 1985a), though they are particularly active in the Leguminosae. The DAO found in pea seedlings (Pisum satiuum) was the subject of early investigations by Werle in Germany (Werle et al., 1961) and by Mann and his co-workers in England (Hill & Mann, 1968). This DAO was purified to homogene...

FAD-linked oxidases constitute a class of enzymes which catalyze dehydrogenation as a fundamental biochemical reaction, followed by reoxidation of reduced flavin. Here, we present high-resolution crystal structures showing the flavoenzyme 6-hydroxy-l-nicotine oxidase in action. This enzyme was trapped during catalytic degradation of the native substrate in a sequence of discrete reaction states...