ANAEROBIC TOLUENE MINERALIZATION PATHWAY IN AZOARCUS TOLULYTICUS SP TOL 4

SIR提供L-[4 '-'80]酪氨酸; IG醌类代表新的 发现一类由翻译后形成的有机辅因子 芳族氨基酸的羟基化，从而使它们 在tenzyme活性位点用作氧化还原催化剂。 的 三羟基苯丙氨酸辅因子（TPQ）存在于胺氧化酶（AO）中， 在那里它催化有机胺氧化成醛。 这 通过胺攻击C5羰基引发反应， 然后氧化成亚胺，随后释放出 醛。 还原的氨基醌醇辅因子被再氧化成 醌在两个单电子步骤涉及半醌 中间体 该再氧化反应利用Cu 2+作为直接氧化剂。 电子受体和O2作为末端电子受体。 共振 拉曼（RR）光谱已被证明是一种优秀的技术， 研究蛋白质中的醌辅因子。 这些发色团产生 强烈增强的光谱，其振动模式对于每个 余因子的类型; 在我们研究AO的TPQ辅因子时， 反应周期，我们能够确定氧化态的 醌和催化中间体的RR光谱。 这些研究 借助了同位素和一系列合成的 模型，为振动提供了更坚实的结构基础， 分配任务。 未来的方向将是阐明 生物合成，提供有关催化的详细信息 反应性，并确定新的醌辅因子的结构 其他酶。

The SIR provided L-[4'-'80]Tyrosine; Ig Quinones represent a newly discovered class of organic cofactors formed by postranslational hydroxylation of aromatic an-iino acids, thereby allowing them to servie as redox catalysts at tenzyme active sites. The trhydroxyphenylalanine cofactor, TPQ, is found in amine oxidases (AO) where it catlyzes the oxidation of organic amines to aldehydes. This reaction is initiated by amine attack at the C5 carbonyl group, followed by oxidation to an imine and subsequent release of an aldehyde. The reduced aminoquinol cofactor is reoxidezed to the quinone in two one- electron steps involving a semiquinone intermediate. This reoxidation reaction utilizes Cu2+ as an immediate electron acceptr and 02 as the terminal electron acceptor. Resonance Raman (RR) spectroscopy has proved to be an excellent technique for studying quinone cofactors in proteins. These chromophores produce strongly enhanced spectra whose vibrational pattern is unique for each type of cofactor;. In our study of the TPQ cofactor of AO during its reaction cycle we were able to identify oxidation states of the quinone and catalytic intermediates by RR spectroscoy. These studies were aided by the use of isotopes and an extensive set of synthetic models that provided a firmer structural basis for vibrational assignments. Future directions will be to elucidate the mechanissm of biosynthesis, to provide detailed information about catalytic reactivity, and to identify the structures of novel quinone cofactors in other enzymes.