BBB : Vol. 65 (2001) , No. 5 pp.1112-1118

Adenine Deaminase Activity of the yicP Gene Product of Escherichia coli

Hiroshi MATSUI¹⁾, Megumi SHIMAOKA¹⁾, Hisashi KAWASAKI¹⁾, Yasuhiro TAKENAKA²⁾ and Osamu KURAHASHl¹⁾

1) Fermentation & Biotechnology Laboratories, Ajinomoto Co., Inc.
2) Aminoscience Laboratories, Ajinomoto Co., Inc.

(Received October 26, 2000)
(Accepted December 28, 2000)

During previous work on deriving inosine-producing mutants of Escherichia coli, we observed that an excess of adenine added to the culture medium was quickly converted to hypoxanthine. This phenomenon was still apparent after disruption of the known adenosine deaminase gene (add) on the E. coli chromosome, suggesting that, like Bacillus subtilis, E. coli has an adenine deaminase. As the yicP gene of E. coli shares about 35% identity with the B. subtilis adenine deaminase gene (ade), we cloned yicP from the E. coli genome and developed a strain that overexpressed its product. The enzyme was purified from a cell extract of E. coli harboring a plasmid containing the cloned yicP gene, and had significant adenine deaminase [EC 3.5.4.2] activity. It was deduced to be a homodimer, each subunit having a molecular mass of 60 kDa. The enzyme required manganese ions as a cofactor, and adenine was its only substrate. Its optimum pH was 6.5-7.0 and its optimum temperature was 60°C. The apparent K_m for adenine was 0.8 mM.

Key words:

yicP gene; adenine deaminase; Escherichia coli; inosine production

	To cite this article:
	Hiroshi MATSUI, Megumi SHIMAOKA, Hisashi KAWASAKI, Yasuhiro TAKENAKA and Osamu KURAHASHl, “Adenine Deaminase Activity of the yicP Gene Product of Escherichia coli”, Biosci. Biotechnol. Biochem., Vol. 65, 1112-1118 (2001) .

	doi:10.1271/bbb.65.1112
	JOI JST.JSTAGE/bbb/65.1112