The mechanisms of pyridoxal 5′-phosphate (PLP) dependent enzymes require substrates to form covalent “external aldimine” intermediates, which absorb light strongly between 410 nm and 430 nm. Aspartate aminotransferase (AAT) is a prototypical PLP ...

2017年10月16日 · Here we report the neutron crystal structure of a PLP-dependent enzyme, aspartate aminotransferase (AAT), a fold-type I PLP-dependent enzyme that reversibly converts l -aspartate and...

In aspartate aminotransferase (AAT), an extended hydrogen bond network is coupled to the pyridinyl nitrogen of the PLP, influencing the electrophilicity of the cofactor. This network, which involves residues Asp-222, His-143, Thr-139, His-189, and structural waters, is located at the edge of PLP opposite the reactive Schiff base.

2023年10月4日 · Pyridoxal phosphate (PLP) dependent enzymes were previously classified into alpha, beta and gamma classes, based on the chemical characteristics (carbon atom involved) of the reaction they catalyzed.

2020年1月1日 · Our NBO analysis on external aldimine models of AAT provides evidence that hyperconjugation enhances PLP-dependent catalysis through transition state stabilization and is manifested in several types of PLP-dependent enzymes where the Dunathan alignment occurs.

2014年2月15日 · Aspartate aminotransferase (AAT) is a prototypical pyridoxal 5′-phosphate (PLP) dependent enzyme that catalyzes the reversible interconversion of l-aspartate and α-ketoglutarate with oxalacetate and l-glutamate via a ping-pong catalytic cycle in which the pyridoxamine 5′-phosphate enzyme form is an intermediate.

2017年4月7日 · In aspartate aminotransferase (AAT), an extended hydrogen bond network is coupled to the pyridinyl nitrogen of the PLP, influencing the electrophilicity of the cofactor. This network, which involves residues Asp-222, His-143, Thr-139, His-189, and structural waters, is located at the edge of PLP opposite the reactive Schiff base.

2010年12月1日 · 天冬氨酸转氨酶 (AAT) 是一种典型的 PLP 依赖性酶，可催化天冬氨酸和 α-酮戊二酸与草乙酸和谷氨酸的可逆相互转化。 根据动力学同位素效应研究，已知天冬氨酸外部醛亚胺 C (α)-H 键去质子化生成碳阴离子醌类中间体在热 AAT 反应中部分限制速率。 基于溶液中席夫碱的研究，我们发现 430 nm 外部醛亚胺吸收 带的激发增加了 AAT 的稳态催化活性，这归因于 C (α)-H 去质子化的光增强。 蓝光 (250 mW) 照明观察到 WT AAT 活性增强 2.3 倍，无活性 K258A 突 …

Aspartate aminotransferase (AAT) is a prototypical PLP-dependent enzyme that catalyzes the reversible interconversion of aspartate and α-ketoglutarate with oxalacetate and glutamate. From kinetic isotope effects studies, it is known that deprotonation of the aspartate external aldimine C α −H bond to give a carbanionic quinonoid ...

2011年4月21日 · The aspartate aminotransferase (AAT) enzyme utilizes the chromophoric pyridoxal 5'-phosphate (PLP) cofactor to facilitate the transamination of amino acids. Recently, we demonstrated that, upon exposure to blue light, PLP forms a reactive triplet state that rapidly (in microseconds) generates the hi …