Generation and characterization of caprine chymosin in corn seed

• The paper was the first report of the production of caprine chymosin in field food crop.
• The recombinant chymosin protein was successfully expressed and activated in the corn seed.
• The new method to express chymosin has advantages of lower cost and better storage capability.
• This corn seed-derived caprine prochymosin shows promise for use in the dairy industry.

Chymosin is widely used in the dairy industry, and much is produced through recombinant DNA in organisms such as bacteria and tobacco. In this study, we used a new transgenic method to express caprine chymosin in corn seeds with lower cost and better storage capability. The recombinant chymosin protein was successfully expressed at an average level of 0.37 mg/g dry weight, which is 0.27% of the total soluble protein in the corn seed. Prochymosin can be activated to produce a chymosin protein with the ability to induce clotting in milk, similar to the commercial protein. The activity of the purified recombinant chymosin was as high as 178.5 U/mg. These results indicate that we have successfully established a technology for generating corn seed-derived caprine chymosin for potential use in the dairy industry.