Eight of them were found as peptidase-coding DNAs of 4 genes named as NK2-SU1, AprE-SU1, SUBJ-SU1 and KPR-SU1. Difference in nucleotide sequences among these genes amplified with the same pair of primers reached 32%.

• 同一对引物扩增到的基因序列差异性可达到32%25；说明只使用基于已知序列的PCR方法从混合菌中获得新蛋白酶基因是可行的.