The N-glycosylation status affects the ability of HAI-2 to form enzyme–inhibitor complexes with trypsin in solution. Equal amounts of cellular proteins from lysates of Caco-2 cells (A) and the HAI-2 KO Caco-2 cells (B), in which N57Q HAI-2 variant has been transiently expressed, were incubated with different amounts of a trypsin preparation, as indicated at 4°C for 30 min. The reaction was terminated by the addition of 1X SDS-sample buffer. The samples were analyzed by immunoblot for HAI-2 species and trypsin-HAI-2 complexes using the HAI-2 mAb. HAI-2 monomer and HAI-2 complexes with trypsin are indicated.