National Renewable Energy Laboratory, Golden, CO, USA.
Methods Mol Biol. 2020;2096:125-139. doi: 10.1007/978-1-0716-0195-2_10.
The metabolic enzymes like any enzymes generally display globular architecture where secondary structure elements and interactions between them preserve the spatial organization of the protein. A typical enzyme features a well-defined active site, designed for selective binding of the reaction substrate and facilitating a chemical reaction converting the substrate into a product. While many chemical reactions could be facilitated using only the functional groups that are found in proteins, the large percentage or intracellular reactions require use of cofactors, varying from single metal ions to relatively large molecules like numerous coenzymes, nucleotides and their derivatives, dinucleotides or hemes. Quite often these large cofactors become important not only for the catalytic function of the enzyme but also for the structural stability of it, as those are buried deep in the enzyme.
代谢酶与其他酶一样，通常呈现球状结构，其中二级结构元件和它们之间的相互作用保持蛋白质的空间组织。典型的酶具有明确的活性位点，用于选择性结合反应底物，并促进将底物转化为产物的化学反应。虽然仅使用蛋白质中发现的功能基团就可以促进许多化学反应，但大多数细胞内反应需要使用辅助因子，从单个金属离子到相对较大的分子，如许多辅酶、核苷酸及其衍生物、二核苷酸或血红素。这些大的辅助因子通常不仅对酶的催化功能，而且对其结构稳定性都很重要，因为它们深埋在酶中。
