Closing the gap between the increasing availability of complete genome sequences and the discovery of novel enzymes in novel metabolic pathways is a significant challenge. Here, we review recent examples of assignment of in vitro enzymatic activities and in vivo metabolic functions to uncharacterized proteins, with a focus on enzymes and metabolic pathways involved in the catabolism and biosynthesis of monosaccharides and polysaccharides. The most effective approaches are based on analyses of sequence-function space in protein families that provide clues for the predictions of the functions of the uncharacterized enzymes. As summarized in this Opinion, this approach allows the discovery of the catabolism of new molecules, new pathways for common molecules, and new enzymatic chemistries.

缩小完整基因组序列可用性的增加与在新代谢途径中发现新酶之间的差距是一项重大挑战。在这里，我们回顾了最近分配体外酶活性和体内的例子未表征蛋白质的代谢功能，重点是参与单糖和多糖的分解代谢和生物合成的酶和代谢途径。最有效的方法是基于对蛋白质家族中序列功能空间的分析，为预测未表征的酶的功能提供线索。正如本意见中总结的那样，这种方法可以发现新分子的分解代谢、常见分子的新途径和新的酶化学。