Author ORCID Identifier

https://orcid.org/0000-0002-2956-9781

Document Type

Article

Publication Date

10-2011

Publication Title

Journal of Computational Chemistry

Volume

32

Issue

5

First Page

822

Last Page

834

DOI

10.1002/jcc.21661

Abstract

In humans, uroporphyrinogen decarboxylase is intimately involved in the synthesis of heme, where the decarboxylation of the uroporphyrinogen‐III occurs in a single catalytic site. Several variants of the mechanistic proposal exist; however, the exact mechanism is still debated. Thus, using an ONIOM quantum mechanical/molecular mechanical approach, the mechanism by which uroporphyrinogen decarboxylase decarboxylates ring D of uroporphyrinogen‐III has been investigated. From the study performed, it was found that both Arg37 and Arg50 are essential in the decarboxylation of ring D, where experimentally both have been shown to be critical to the catalytic behavior of the enzyme. Overall, the reaction was found to have a barrier of 10.3 kcal mol−1at 298.15 K. The rate‐limiting step was found to be the initial proton transfer from Arg37 to the substrate before the decarboxylation. In addition, it has been found that several key interactions exist between the substrate carboxylate groups and backbone amides of various active site residues as well as several other functional groups.

Available for download on Saturday, May 13, 2119

Share

COinS