Ruggiero C E, Dooley D M
Department of Chemistry and Biochemistry, Montana State University, Bozeman 59717, USA.
Biochemistry. 1999 Mar 9;38(10):2892-8. doi: 10.1021/bi9824994.
The stoichiometry of the topa quinone biogenesis reaction in phenylethylamine oxidase from Arthrobacter globiformis (AGAO) has been determined. We have shown that the 6e- oxidation of tyrosine to topa quinone (TPQ) consumes 2 mol of O2 and produces 1 mol of H2O2/mol of TPQ formed. The rate of H2O2 production is first-order (kobs = 1.0 +/- 0.2 min-1), a rate only slightly lower than the rate of TPQ formation directly determined previously (kobs = 1.5 +/- 0.2 min-1). This gives the following net reaction stoichiometry for TPQ biogenesis: E-Tyr + 2O2 --> E-TPQ + H2O2. This stoichiometry is in agreement with recently proposed mechanisms for TPQ biogenesis, and rules out several possible alternatives.
已确定球形节杆菌苯乙胺氧化酶（AGAO）中对苯二酚醌生物合成反应的化学计量关系。我们已经表明，酪氨酸6电子氧化生成对苯二酚醌（TPQ）消耗2摩尔O₂，每摩尔生成的TPQ产生1摩尔H₂O₂。H₂O₂生成速率为一级反应（观测速率常数kobs = 1.0±0.2 min⁻¹），该速率仅略低于先前直接测定的TPQ生成速率（观测速率常数kobs = 1.5±0.2 min⁻¹）。这给出了TPQ生物合成的如下净反应化学计量关系：E-酪氨酸 + 2O₂ → E-TPQ + H₂O₂。该化学计量关系与最近提出的TPQ生物合成机制一致，并排除了几种可能的替代机制。
