Arnold Ulrich
Institute of Biochemistry and Biotechnology, Martin-Luther University, Kurt-Mothes-Str. 3, 06120, Halle, Germany.
Biotechnol Lett. 2009 Aug;31(8):1129-39. doi: 10.1007/s10529-009-0002-9. Epub 2009 Apr 29.
The biotechnological application of enzymes necessitates a permanent quest for new biocatalysts. Among others, improvement of catalytic activity, modification of substrate specificity, or increase in stability of the enzymes are desirable goals. The exploration of homologous enzymes from various sources or DNA-based methods, like site-directed mutagenesis or directed evolution, yield an incredible variety of biocatalysts but they all rely on the restricted number of canonical amino acids. Chemistry offers an almost unlimited palette of additional modifications which can endow the proteins with improved or even completely new properties. Numerous techniques to furnish proteins with non-natural amino acids or non-proteinogenic modules have been introduced and are reviewed with special focus on expressed protein ligation, a method that combines the potential of protein biosynthesis and chemical synthesis.
酶的生物技术应用需要不断寻找新的生物催化剂。其中，提高催化活性、改变底物特异性或增强酶的稳定性是理想的目标。从各种来源探索同源酶或基于DNA的方法，如定点诱变或定向进化，可产生种类繁多的生物催化剂，但它们都依赖于有限数量的标准氨基酸。化学提供了几乎无限的额外修饰选项，可赋予蛋白质改进的甚至全新的特性。已经引入了许多为蛋白质提供非天然氨基酸或非蛋白质ogenic模块的技术，并特别关注表达蛋白连接这一方法进行了综述，该方法结合了蛋白质生物合成和化学合成的潜力。
