کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5395404 1505662 2011 11 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Computational studies on Schiff-base formation: Implications for the catalytic mechanism of porphobilinogen synthase
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Computational studies on Schiff-base formation: Implications for the catalytic mechanism of porphobilinogen synthase
چکیده انگلیسی
Schiff bases are common and important intermediates in many bioenzymatic systems. The mechanism by which they are formed, however, is dependent on the solvent, pH and other factors. In the present study we have used density functional theory methods in combination with appropriate chemical models to get a better understanding of the inherent chemistry of the formation of two Schiff bases that have been proposed to be involved in the catalytic mechanism of porphobilinogen synthase (PBGS), a key enzyme in the biosynthesis of porphyrins. More specifically, we have investigated the uncatalysed reaction of its substrate 5-aminolevulinic acid (5-ALA) with a lysine residue for the formation of the P-site Schiff base, and as possibly catalysed by the second active site lysine, water or the 5-ALA itself. It is found that cooperatively both the second lysine and the amino group of the initial 5-ALA itself are capable of reducing the rate-limiting energy barrier to 14.0 kcal mol−1. We therefore propose these to be likely routes involved in the P-site Schiff-base formation in PBGS.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Computational and Theoretical Chemistry - Volume 963, Issues 2–3, February 2011, Pages 479-489
نویسندگان
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