The present invention provides a method for removing cysteine caps from antibodies and re-capping the antibodies with cysteine molecules. The methods include, inter alia, culturing a host cell comprising a protein molecule having at least one capped engineered cysteine residue, and contacting the cell culture with cystine. Dissolved oxygen levels can be manipulated in the cell culture to further enhance the removal and re-capping process.本發明提供一種用於自抗體移除半胱胺酸帽且用半胱胺酸分子再加帽該等抗體之方法。該等方法尤其包括培養宿主細胞，該宿主細胞包含具有至少一個工程化加帽半胱胺酸殘基之蛋白質分子，以及使該細胞培養物與胱胺酸接觸。可操控細胞培養物中之溶解氧水準以進一步促進該移除及再加帽製程。
