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Serine hydroxymethyltransferase from the silkworm Bombyx mori : Identification, distribution, and biochemical characterization
Author(s) -
Haque Mohammad R.,
Hirowatari Aiko,
Nai oko,
Furuya Shigeki,
Yamamoto Kohji
Publication year - 2019
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.21594
Subject(s) - serine hydroxymethyltransferase , bombyx mori , serine , biochemistry , biology , amino acid , complementary dna , enzyme , homology (biology) , escherichia coli , glycine , microbiology and biotechnology , recombinant dna , enzyme kinetics , gene , active site
Serine hydroxymethyltransferase (SHMT) catalyzes the interconversion of serine and tetrahydrofolate (THF) to glycine and methylenetetrahydrofolate. cDNA encoding Bombyx mori SHMT (bmSHMT) was cloned and sequenced. The deduced amino acid sequence consisted of 465 amino acids and was found to share homology with other SHMTs. Recombinant bmSHMT was overexpressed in Escherichia coli and purified to homogeneity. The enzyme showed optimum activity at pH 3.0 and 30°C and was stable under acidic conditions. The K m and k cat /K m values for THF in the presence of Nicotinamide adenine dinucleotide phosphate (NADP + ) were 0.055 mM and 0.081 mM −1 s −1 , respectively, whereas those toward NADP + were 0.16 mM and 0.018 mM −1 s −1 and toward l ‐serine were 1.8 mM and 0.0022 mM −1 s −1 , respectively. Mutagenesis experiments revealed that His119, His132, and His135 are important for enzymatic activity. Our results provide insight into the roles and regulation mechanism of one‐carbon metabolism in the silkworm B. mori.