This report is about α-Amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD), a widespread enzyme that occupies a key position at the branching point of two very important metabolic pathways (Martynowski, et al, 2006). Analysis of the 3-D structure of ACMSD, from Pseudomonas fluorescens, has lead to the discovery of a novel, transition metal-dependent, non-oxidative decaboxylation reaction mechanism. This mechanism is unprecedented among all currently characterized decarboxylases (Martynowski, et al, 2006). Sequence analysis of ACMSD suggests that it belongs to the amidohydrolase superfamily and is the first decarboxylase in the family (Li, et al, 2006).

ACMSD is of interest as a drug target due to its ability to regulate whether cells produce quinolinic acid for NAD biosynthesis or produce acetyl-CoA to enter the citric acid cycle (Pucci, et al, 2007). ACMSD is also of interest with respect to environmental pollution issues, since it is also involved in the 2-nitrobenzoate pollutant degradation pathway (Hasegawa et al, 2000).

Introduction ACMSD and decarboxylases background.

ACMSD Importance Why does ACMSD decarboxylase use a novel mechanism.

Pathway Regulation by ACMSD Discover the significance of the regulated pathways.

How the ACMSD Structure was Discovered Methods used to determine the crystal structure of ACMSD.

Structure Analysis ACMSD belongs to the amidohydrolase superfamily.

Reaction Mechanisms Proposed reactions catalyzed by ACMSD.

Summary Relevance to human health and pollution remediation.