Acetylornithine aminotransferase TM1785 performs multiple functions in the hyperthermophile Thermotoga maritima

FEBS Letters

article

Tetsuya Miyamoto¹  Yasuaki Saitoh¹  Masumi Katane¹  Masae Sekine¹  Kumiko Sakai-Kato¹  Hiroshi Homma¹ 

[1] Graduate School of Pharmaceutical Sciences, Kitasato University

关键词: acetylornithine aminotransferase;    amino acid racemase;    cysteine lyase;    d-amino acid metabolism;    multifunctional enzyme;    Thermotoga maritima;   

DOI  :  10.1002/1873-3468.14222

来源: John Wiley & Sons Ltd.

【 摘 要 】

The hyperthermophilic bacterium Thermotoga maritima peptidoglycan contains unusual d -lysine alongside typical d -alanine and d -glutamate. We previously identified lysine racemase and threonine dehydratase, but knowledge of d -amino acid metabolism remains limited. Herein, we identified and characterized T .  maritima acetylornithine aminotransferase TM1785. The enzyme was most active towards acetyl- l -ornithine, but also utilized l -glutamate, l -ornithine and acetyl- l -lysine as amino donors, and 2-oxoglutarate was the preferred amino acceptor. TM1785 also displayed racemase activity towards four amino acids and lyase activity towards l -cysteine, but no dehydratase activity towards l -serine, l -threonine or corresponding d -amino acids. Catalytic efficiency ( k cat / K m ) was highest for aminotransferase activity and lowest for racemase activity. TM1785 is a novel acetylornithine aminotransferase associated with l -arginine biosynthesis that possesses two additional distinct activities.

【 授权许可】

Unknown