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David J Merkler

University of South Florida, USA

Title: N-acyltransferases and their role in fatty acid amide biosynthesis

Biography

David J Merkler obtained a PhD in Biochemistry from Pennsylvania State University in 1985 and completed Postdoctoral Fellowships in Enzymology at Temple
University School of Medicine (1985-1987) and the Albert Einstein College of Medicine (1987-1989). His next position was as Senior Scientist at Unigene
Laboratories, Inc. involved in the in vitro production of a peptide hormone, calcitonin. In 1995, he moved back to academia as a Professor of Chemistry and
Biochemistry fi rst at Duquesne University (1995-1999) and then the University of South Florida (1999-present). His laboratory has been interested in the fatty
amides: identifi cation and characterization of the fatty acid amides (Lipidomics), identifi cation and characterization of the enzymes of fatty acid amide biosynthesis
(Enzymology and Structural Biology), and changes in the fatty acid amidome after targeted enzyme knock-out (subtraction lipidomics).

Abstract

Fatty acid amides are a family of cell signaling lipids with the general structure of R-CO-NH-Y. Th is structural simplicity belies
a wealth of diversity amongst this lipid family as the R-group is derived from fatty acids (R-COOH) and the Y-group is derived
from biogenic amines (H2N-Y). Th e fatty acid amide family is divided into classes, defi ned by parent amines. Examples include the
N-acylethanolamines (NAEs, R-CO-NH-CH2-CH2OH) and the N-acylglycines (NAGs, R-CO-NH-CH2-COOH). Other classes of
fatty acid amides are known. Th e best known fatty acid amide is N-arachidonoylethanolamine (anandamide), a fatty acid amide found
in the human brain that binds to the cannabinoid receptors. We have a long interest in the enzymes of fatty acid amide biosynthesis.
We identifi ed an enzyme that oxidizes the NAGs to the primary fatty acid amides and showed that inhibiting this enzyme led to the
cellular accumulation of the NAGs. We have characterized several insect N-acyltransferases (from D. melanogaster, B. mori, and T.
castaneum) that catalyze the acyl-CoA-dependent formation of fatty acid amides from an amine acyl-acceptor substrate. Knock-out
experiments in D. melanogaster validate our in vitro substrate specifi c studies demonstrating that one novel N-acyltransferases, arylalkyl
N-acyltransferase-like 2 (AANATL2), does catalyze the formation of N-acyldopamines in vivo. We developed a straightforward
platform technology to rapidly identify substrates for our panel of uncharacterized insect N-acyltransferases. Our application of this
technology leads to identifi cation of an enzyme in D. melanogaster, agmatine N-acetyltransferase (AgmNAT), which catalyzes the
formation of N-acetylagmatine, a virtually unknown metabolite. We have determined the X-ray structure of AgmNAT. Our work on
AgmNAT hints at an unknown reaction in arginine metabolism and points to a novel class on fatty acid amides, the N-acylagmatine.
Th e presentation will also include our results on the kinetic and chemical mechanisms of the novel N-acyltransferases.