The present disclosure relates to a process for preparing antibodies with a defined glycosylation pattern, in particular antibodies with a glycan terminating in an N-acetylglucosamine. The antibodies of the disclosure are suitable for use in a process to conjugate a payload thereto. The disclosure also extends to molecules obtained and obtainable from the process disclosed herein, novel molecules and intermediates, compositions comprising said molecules and uses of the molecules and compositions, particularly in treatment, for example in the treatment of cancer.