Conformational requirements of substrates for activity with phenylethanolamine N-methyltransferase

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

Research output: Contribution to journalArticle

12 Citations (Scopus)

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-phenylethanolamine 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
StatePublished - 1988
Externally publishedYes

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Phenylethanolamine N-Methyltransferase
Catalytic Domain
Substrates
Conformations
Derivatives
Enzymes
Catalysis
Isomers
Hydroxyl Radical
Epinephrine
Norepinephrine
Binding Sites
1,2,3,4-tetrahydroisoquinoline

ASJC Scopus subject areas

  • Organic Chemistry

Cite this

Conformational requirements of substrates for activity with phenylethanolamine N-methyltransferase. / Grunewald, Gary L.; Ye, Qizhuang; Kieffer, Lynda; Monn, James A.

In: Journal of Medicinal Chemistry, Vol. 31, No. 1, 1988, p. 169-171.

Research output: Contribution to journalArticle

Grunewald, Gary L. ; Ye, Qizhuang ; Kieffer, Lynda ; Monn, James A. / Conformational requirements of substrates for activity with phenylethanolamine N-methyltransferase. In: Journal of Medicinal Chemistry. 1988 ; Vol. 31, No. 1. pp. 169-171.
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