Endopeptidase , BAPA , from sterile line at trinucleate stage showed cysteine - and serine types , and also part of type with metalloprotease , but it was the serine type only in maintainer line .
不育系三核期含有的BAPA内肽酶包括半胱氨酸型、丝氨酸型,以及部分含金属酶类;