Exatration, Structural Analysis And Bioactivity Of Peptidoglycan From L.PARACASEISUBP.PARACASEIX12

In this study, peptidoglycan was extracted from L.paracasei subp. Paracasei X12 cell wall which was preliminary screened with function of anti-colontumor. Using oxidation resistance ability and the inhibition of HT-29 cell proliferation as evaluation method, PG-A30 and PG-D70 were screened with biological activity among peptidoglycan which was graded alcohol precipitation with ethanol. Using combined method of instruments and chemistry to analysis chemical structure of PG-A30 and PG-D70. And finally to explore the relationship between structure and function, it will become waste into treasure, and give their potential value.After cultured by MRS liquid medium, L. paracasei subp. paracasei X12 removed teichoic acid、axunge and protein by trichloroacetic acid method in order to obtain polysaccharide which has been freeze dried. PG-A30、PG-B40、PG-C50 and PG-D70 were precipitated under conditions of 30、40、50 �'� 70% ethyl alcohol. Observed under a transmission electron microscope, PG-A30 was cystic and transparent and still retains thallus shape with characteristic lysozyme activity. It was concluded that antioxidant capacity of the PG-D70 is the strongest; PG-A30 can inhibit the proliferation of HT-29 cells better. Comparing content of hexosamine, protein and phosphorus, the differences between PG-A30 and PG-D70 were non-significant. However, the differences between PG-A30、PG-D70 and L. paracaseisubp. Paracasei X12 were very significant.Analyzing PG-A30 by thin-layer chromatography、amino acid and infrared scanning, it showed PG-A30 consists of three parts. N-acetylglucosamine is joined to N-Acetylmuramic acid by 1�'glycosidic bond; glutamic acid、lysine、aspartic acid and alanine make up tail peptide.Through preliminary structure-activity relationship research, it was concluded that the length of carbohydrate chain has great influence on the antioxidant activity and inhibition of HT-29 cell proliferation of PG-A30.