L-半胱氨酸是 β-内酰胺类抗生素的一个前体。半胱胺甲硫氨酸 - γ-裂解酶 (1,由 mec B基因编码 )是一个裂解半胱胺甲硫氨酸释放半胱氨酸的酶 ,在亮氨酸补充培养基中它是高产头孢菌素所需的酶。通过 mec B基因在产黄支顶孢霉中的扩增 ,所获得的几个转化子的头孢菌素产量提高 10 L-cysteine ​​is a precursor of beta-lactam antibiotics. Cysteamine methionine-γ-lyase (1, encoded by the mec B gene) is an enzyme that cleaves cysteine ​​methionine to release cysteine, which is highly productive in leucine replacement medium Cephalosporins required for the enzyme. The cephalosporin production of several transformants obtained was increased by amplification of the mec B gene in C. acremonium