type	Journal Article
authors	Hayashi M, Okada A, Yamamoto K1, Okugochi T, Kusaka C, Kudou D, Nemoto M, Inagaki J, Hirose Y, Okajima T, Tamura T, Soda K, Inagaki K
title	Gene cloning, recombinant expression, purification and characterization of l-methionine decarboxylase from Streptomyces sp. 590.
journal	J Biochem (Tokyo)
Activity	4.1.1.57
Family	4.1.1.57
sel	selected
ui	28003434
year	(2017)
volume	161
number	4
pages	389-98
abstract	l-Methionine decarboxylase (MetDC) from Streptomyces sp. 590 depends on pyridoxal 5'-phosphate and catalyzes the non-oxidative decarboxylation of l-methionine to produce 3-methylthiopropylamine and carbon dioxide. MetDC gene (mdc) was determined to consist of 1,674 bp encoding 557 amino acids, and the amino acid sequence is similar to that of l-histidine decarboxylases and l-valine decarboxylases from Streptomyces sp. strains. The mdc gene was cloned and recombinant MetDC was heterologously expressed by Escherichia coli. The purification of recombinant MetDC was carried out by DEAE-Toyopearl and Ni-NTA agarose column chromatography. The recombinant enzyme was homodimeric with a molecular mass of 61,000 Da and showed optimal activity between 45 to 55 °C and at pH 6.6, and the stability below 30 °C and between pH 4.6 to 7.0. l-Methionine and l-norleucine were good substrates for MetDC. The Michaelis constants for l-methionine and l-norleucine were 30 and 73 mM, respectively. The recombinant MetDC (0.50 U/ml) severely inhibited growth of human tumour cells A431 (epidermoid ovarian carcinoma cell line) and MDA-MB-231 (breast cancer cell line), however showed relatively low cytotoxicity for human normal cell NHDF-Neo (dermal fibroblast cell line from neonatal foreskin). This study revealed the properties of the gene and the protein sequence of MetDC for the first time.
last changed	2017/11/28 14:06