题目

Where does this conversation probably take place? A . In a shop. B . In a factory. C . In the woman's house. 答案：B牛胰岛素由51个氨基酸组成的两条多肽链构成，它们通过二硫键结合起来，此分子共含有肽键数（　　） A、49个B、50个C、51个D、52个