کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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2021885 | 1069266 | 2007 | 9 صفحه PDF | دانلود رایگان |
Serine hydroxymethyltransferase (SHMT) plays a key role in cell physiology as it participates in the different interconversion pathway of folate coenzymes, provides almost exclusively folate one carbon fragments for the biosynthesis of a variety of end products. For the first time, Mycobacterium leprae glyA gene, encodes the enzyme serine hydroxymethyltransferase, has been cloned in Escherichia coli, over-expressed and purified the protein product (mlSHMT) for folding and stability studies under various denaturating conditions. The recombinant mlSHMT exists as homo-dimer of molecular mass about 90 kDa under physiological conditions . The studies on catalytic properties of mlSHMT show that the enzyme catalyzes the H4-folate dependent retro-aldol cleavage of l-serine, however, d-alanine dependent transaminase activity was absent in the enzyme. Further analysis of the enzyme kinetics for hydroxymethyltransferase reaction for mlSHMT demonstrates a comparable Km value for l-serine to SHMTs from other sources but significantly lower catalytic efficiency (kcat/Km). The mlSHMT is resistant to alkaline denaturation and exist as apo-dimer up to pH 10.5. Urea and guanidinium chloride induces dissociation of mlSHMT dimer into monomer at low denaturant concentrations, and leads to loss of enzymatic activity.
Journal: Protein Expression and Purification - Volume 55, Issue 1, September 2007, Pages 189–197