Abstract:

Objective: The L68Q mutation in the cystatin C (cC) gene can form amyloid through dimers at the initial stage. The
curcumin was used to explore the growth of yeast and the quantity of secretory cC in mutated recombinant yeast Pichia pastoris
as well as its inhibitory effect on amyloid accumulation of cC. Methods: The extraction of curcumin was optimized using response
surface methodology. The inhibitory effect of curcumin on the growth of recombinant cC yeast was measured. The quantity of cC,
secreted by yeast in media with curcumin at different concentrations, was evaluated by SDS-PAGE. The degree of cC amyloid in
the presence of curcumin was explored by Congo red staining. Results: The optimal extraction conditions for solid/solvent ratio,
ultrasonic power and time were 30:1 (mL/g), 300 W and 15 min, respectively. Under these conditions, the yield of curcumin was 3.97
mg/g. The inhibitor effect of curcumin on recombinant yeast growth was relatively mild, but increased curcumin concentration
could more effectively inhibit the secretion of cC and cC amyloid. Conclusion: Curcumin can inhibit the growth, protein secretion
of recombinant yeast and amyloidogenic characteristics of recombinant cystatin.

Key words: curcumin, recombinant cystatin, response surface methodology