US EPA

6603360 

Journal Article 

PHENYLETHANOLAMINE IS A SPECIFIC SUBSTRATE FOR TYPE-B MONO-AMINE OXIDASE 

Edwards, DJ; , 

1978 

1 

Life Sciences
ISSN: 0024-3205
EISSN: 1879-0631 

PERGAMON-ELSEVIER SCIENCE LTD 

OXFORD 

23 

11 

1201-1208 

English 

713694 

10.1016/0024-3205(78)90355-7 

WOS:A1978FR15800012 

https://www.scopus.com/inward/record.uri?eid=2-s2.0-0018272224&doi=10.1016%2f0024-3205%2878%2990355-7&partnerID=40&md5=f36d9c3195390dc3cbde3caef5f7a214
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The characteristics of phenylethanolamine as both a competitive inhibitor and as a substrate for monoamine oxidase (MAO) were studied using rat brain and liver homogenates. Although phenylethanolamine, even at high concentrations (1 mM), produced minimal inhibition of MAO when serotonin (a substrate for type A MAO) was used as the substrate, it was a potent competitive inhibitor (Ki=11 μM) of the deamination of phenylethylamine (a substrate for type B MAO). When phenylethanolamine was used as a substrate, deprenyl, a selective inhibitor of type B MAO, was found to produce a single sigmoid inhibition curve at low concentrations of the inhibitor (pI50=7.5). These results indicate that phenylethanolamine is a specific substrate for type B MAO. Identification of the products formed under the assay conditions show that phenylethanolamine is converted to both mandelic acid and phenylethylene glycol by liver homogenates but only to the latter, neutral metabolite by brain homogenates. © 1978.