Identification of l-histidine oxidase activity in Achromobacter sp. TPU 5009 for l-histidine determination

An enzyme showing l-histidine oxidase (HisO) activity by the formation of hydrogen peroxide was newly purified from Achromobacter sp. TPU 5009. This found to be a heterodimer two proteins (molecular mass, 53.8 and 58.3 kDa), partial determination which indicated they are homologs ammonia-lyase (AchHAL) urocanate hydratase (AchURO). The stable in pH range 5.0–11.0, with >90% original maintained below 60°C at 7.0. To characterize AchHAL AchURO, each their genes cloned expressed heterologous expression system. Heterologous catalyzed elimination α-amino group ammonia, while AchURO hydration imidazolone propionate. Since propionate is highly unstable presence oxygen neutral pH, it immediately decomposed non-enzymatically produced. Our results indicate that this natural apparent HisO composed formed after spontaneous decomposition