Quinoproteins: Characterization and Mechanism

这项建议的目的是利用生物化学和 生物物理方法来进一步表征一类 含有辅因子的酶称为醌蛋白。 的 研究将集中在哺乳动物的醌蛋白，血浆 单胺氧化酶、肾二胺氧化酶和赖氨酰氧化酶。 所有这些酶都被认为含有细菌 辅因子，吡咯喹啉醌，PQQ，但这一结论 现在还不确定 本提案的目标是：（1） 表征含有活性位点辅因子的肽， 二胺氧化酶和赖氨酰氧化酶。 有可能这些 酶具有与血浆单胺氧化酶相同的辅因子， 也就是说，6-羟基多巴; 2）克隆基因并开发一种 血浆单胺氧化酶和肾脏的表达系统 二胺氧化酶; 3）表征Cu 2+的邻近性 和所有三种酶的辅因子位点， 生物物理学方法; 4）启动调查， 6-羟基多巴的生物合成来源。 这些研究将 提供了一个清晰的理解的机械和 这些金属醌蛋白的结构特征，并导致 关于羰基辅因子的性质的共识， 哺乳动物来源的醌蛋白。

The aims of this proposal are to employ biochemical and biophysical methods to further characterize a class of cofactor-containing enzymes called quinoproteins. The research will focus on the mammalian quinoproteins, plasma monoamine oxidase, kidney diamine oxidase and lysyl oxidase. All of these enzymes had been thought to contain the bacterial cofactor, pyrroloquinoline quinone, PQQ, but this conclusion is now in doubt. The objectives of this proposal are 1) to characterize the active site cofactor-containing peptides of diamine oxidase and lysyl oxidase. It is possible that these enzymes have the same cofactor as plasma monoamine oxidase, i.e., 6-hydroxydopa; 2) to clone the genes and develop an expression system for plasma monoamine oxidase and kidney diamine oxidase; 3) to characterize the proximity of the Cu2+ and cofactor sites of all three enzymes using a variety of biophysical methods; and 4) to initiate an investigation of the biosynthetic origin of 6-hydroxydopa. These studies will provide a clear understanding of the mechanistic and structural features of these metalloquinoproteins and lead to a consensus concerning the nature of the carbonyl cofactor in quinoproteins of mammalian origin.