Trypsin inhibitors supplementation

Reduced nitrogen retention was reported when chicks were fed rye diets (18). Supplementation of those diets with amino acids increased the retention of only the supplemented amino acids and not those contributed by the rye. These observations are compatible with the trypsin inhibitor hypothesis of other researchers (9,10). On the other hand, examination of the differences between endosperm and embryo and trypsin inhibitors of barley, wheat, and rye has revealed that, in contrast to certain trypsin inhibitors from leguminous seeds, those from the cereal grains appeared to be relatively weak, nonstoichiometric inhibitors of trypsin (19). 

The effect of purified soybean Kunitz and BBI trypsin inhibitors as dietary supplements (5, 15, or 50 g/kg) on spontaneous pulmonary metastasis of lung carcinoma 3LL cells as well as human ovarian cancer HRA cells was investigated in mice (Ko-bayashi et al., 2004a). Only Kunitz inhibitor inhibited the formation of lung metastasis in a dose-dependent manner. These results suggest that dietary supplementation of Kunitz inhibitor could more efficiently regulate cell metastatic processes than BBI,... 

Kobayashi, H. Y. Fukuda R. Yoshida Y. Kanada S. Nishiyama M. Suzuki N. Kanayama T. Terao. Suppressing effects of dietary supplementation of soybean trypsin inhibitor on spontaneous, experimental and peritoneal disseminated metastasis in mouse model. Int. J. Cancer, 2004a, 112, 519-524. 

Pei et al. (2000) purified MAP-21, a further cuticle-degrading serine protease from M. anisopliae. Fungal cultures were induced by minimal medium supplemented with Cicada exuviae, colloidal chitin, shrimp cuticle, maggot cuticle, horsefly cuticle and silkworm Chrysalis cuticle. The recognition site of the protease occurred to be Arg. Studies with different protease inhibitors have revealed that MAP-21 is a trypsin-like protease. 

Fig. IB. The effect of SAB on the repair kinetics of potentially lethal damage in normal human fibroblasts, Ewing s sarcoma, and human lung adenocarcinoma. No inhibitor (open circles) 8SAB (closed circles). Data points are means 1 standard deviation. Both normal fibroblast and human tumor cell cultures were grown and maintained in Eagle s MEM supplemented with 10% (VA ) fetal bovine serum, streptomycin and penicillin, at S7°C in a humidified chamber of 95% air and 5% CO2. Stock cultures in exponential growth were detached by trypsinization and appropriate cell numbers plated in 25 cm flasks and incubated to permit cell attachment. Inhibitors of poly(ADP-ribose) synthetase (SAB or BZ) were added to the appropriate cultures 2 hr prior to irradiation in air at room temperature. Following irradiation, the cells were exposed to the inhibitors for 24 hr, washed, and replenished with fresh medium. Refeeding was performed every S days and after 10-14 days, cells were fixed and the colonies stained with Giemsa. Only colonies of 50 cells or more were scored as survivors. All experiments were performed in triplicate and the survival data expressed as the mean S.E. of three separate survival experiments.

Supplementing chick diets with a protein fraction, isolated from raw Russet Burbank potato tubers, enriched in proteinase inhibitors, had previously been shown to severely depress their growth (5). The inhibitor-rich fraction contained at least six well characterized inhibitors of mammalian pancreatic digestive proteinases trypsin, chymotrypsin, elastase and carboxypeptidases A and B (5). Since the fraction contained an array of proteinase inhibitors it was not known if CPI contributed to the growth depressing activities. 

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