Conformational requirements of substrates for activity with phenylethanolamine N-methy ltransferase

Gary L. Grunewald, Qizhuang Ye, Lynda Kieffer, James A. Monn

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

β-Phenylethanolamines have long been known to be substrates for the enzyme that converts norepinephrine to epinephrine (phenylethanolamine N-methyltransferase, PNMT, EC 2.1.1.28). In an effort to determine which, if any, particular conformation of the aminoethyl side chain of phenylethanolamines is required for PNMT active site binding and catalysis, we have prepared and evaluated conformationally restricted phenylethanolamine analogues 8-10. The folded phenylethanolamine derivative 4-hydroxy-1, 2, 3, 4-tetrahydroisoquinoline (8) is not a substrate and does not interact with the enzyme active site as an inhibitor as well as 1, 2, 3, 4-tetrahydroisoquinoline (6). In the cyclic 2-aminotetralol systems, only cis-phenylethanolamme derivative 9 demonstrates activity as a PNMT substrate. The corresponding trans isomer 10 is not a substrate, in spite of enhanced active site interactions with respect to the parent analogue (2-aminotetralin, 4). Comparison of the inhibition constants for the folded (8, Ki = 175 μM) and extended (10, Ki = 9 μM) phenylethanolamine analogues strongly suggests that simultaneous binding of both the amino and hydroxyl functionalities to the PNMT active site requires an extended aminoethyl side chain conformation.

Original languageEnglish (US)
Pages (from-to)169-171
Number of pages3
JournalJournal of Medicinal Chemistry
Volume31
Issue number1
DOIs
StatePublished - Jan 1 1988
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Medicine
  • Drug Discovery

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