Study On The Purification And Function Of Casein Glycomacropeptide

Casein Glycomacropeptide(CGMP) is a glycopeptide of64amino acid residues (106-169) derived from the C-terminal of mammalian K-casein. CGMP are formed by chymosin (or pepsin) cleavage of K-casein between Phe105-Met106during the manufacture of cheese. CGMP is heterogeneous due to different glycosylation or phosphorylation. CGMP is known to have various biological functions such as binding cholera toxin and E. coli enterotoxins, inhibiting bacterial and viral adhesion, suppressing gastric secretions, promoting bifidobacterial growth, modulating immune-system responses etc. In this study, we studied the technology conditions for hydrolyzing casein to produce casein glycomacropeptide with chymosin, and found that raw CGMP has growth, acid, adherence-inhibitory activity against the oral opportunistic pathogens S. mutans; and purified it.This experiment has been studied on the CGMP preparation process. Through resorcinol-hydrochloric acid method, we detected the existence of CGMP in hydrolysates compared with standard CGMP. The experimental results showed that: hydrolyzate had the same reaction colour as standard CGMP. The hydrolyzate do contained CGMP accordingly. Subsequently, through the resorcinol-hydrochloric acid method, experiment determined the sialic acid content of hydrolysates, and according to standard curve of CGMP, we calculated that the CGMP content of hydrolysates was50.9%. By using SDS-PAGE method, we determined the existence and molecular weight range of CGMP in hydrosates. The result showed that:the molecular weigh of CGMP was18kDa in the hydrolysates.We has studied on raw CGMP function. Through filter paper method, we studied the inhibitory properties of raw CGMP on the growth of S. mutans. The Experiment found that: the inhibition zone around the filter paper containing raw CGMP was clear and transparent, and it was proved that raw CGMP has inhibitory effect on the growth of S. mutans. Through pH value method, we studied the inhibitory properties of raw CGMP on theacid of S. mutans. The Experiment found that:raw CGMP has inhibitory effect on the acid of S. mutans. Through Turbidimetry method, we studied the inhibitory properties of raw CGMP on the adherence of S. mutans. The Experiment found that:raw CGMP has inhibitory effect on the adherence of S. mutans.Finally, the raw CGMP was isolated by DEAE-52and RP-HPLC one after another.