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Pancreatic secretory trypsin inhibitor (PSTI) is a potent trypsin inhibitor that is mainly found in pancreatic juice. PSTI has been shown to bind specifically to a protein, distinct from trypsin, on the surface of dispersed cells obtained from tissues such as small intestine. In the present study, we affinity-purified the binding protein from the 2% (w/v) Triton X-100-soluble fraction of dispersed rat small-intestinal cells using recombinant rat PSTI. Partial N-terminal sequencing of the purified protein gave a sequence that was identical with the sequence of mouse granzyme A (GzmA), a tryptase produced in cytotoxic lymphocytes. We confirmed the formation of an affinity-cross-linked complex between (125)I-labelled PSTI and recombinant rat GzmA (rGzmA). In situ hybridization and immunostaining revealed the existence of GzmA-expressing intraepithelial lymphocytes in the rat small intestine. We concluded that the PSTI-binding protein isolated from the dispersed cells is GzmA that is produced in the lymphocytes of the tissue. The rGzmA hydrolysed the N -alpha-benzyloxycarbonyl-L-lysine thiobenzyl ester (BLT), and the BLT hydrolysis was inhibited by PSTI. Sulphated glycosaminoglycans, such as fucoidan or heparin, showed almost no effect on the inhibition of rGzmA by PSTI, whereas they decreased the inhibition by antithrombin III. In the present paper, we propose a novel role of PSTI as a GzmA inhibitor.

BackgroundCurry, one of the most popular foods in Japan, contains spices that are rich in potentially antioxidative compounds, such as curcumin and eugenol. Oxidative stress is thought to impair endothelial function associated with atherosclerosis, a leading cause of cardiovascular events. The aim of this study was to determine whether a single consumption of curry meal would improve endothelial function in healthy men.MethodsFourteen healthy male subjects (BMI 23.7 ± 2.7 kg/m2; age 45 ± 9 years) were given a single serving of curry meal or spice-free control meal (180 g of curry or control and 200 g of cooked rice; approximately 500 kcal in total) in a randomized, controlled crossover design. Before and 1 hr after the consumption, fasting and postprandial flow-mediated vasodilation (FMD) responses and other parameters were measured.ResultsThe consumption of the control meal decreased FMD from 5.8 ± 2.4% to 5.1 ± 2.3% (P = 0.039). On the other hand, the consumption of the curry meal increased FMD from 5.2 ± 2.5% to 6.6 ± 2.0% (P = 0.001), and the postprandial FMD after the curry meal was higher than that after the control meal (P = 0.002). Presence of spices in the curry did not alter significantly the systemic and forearm hemodynamics, or any biochemical parameters including oxidative stress markers measured.ConclusionsThese findings suggest that the consumption of curry ameliorates postprandial endothelial function in healthy male subjects and may be beneficial for improving cardiovascular health.Trial registrationUMIN Clinical Trials Registry 000012012.

Membrane-type serine protease 1 (MT-SP1), identical to matriptase, is a re cently identified type II transmembrane serine protease. MT-SP1/matriptase is of consider able interest for the development, homeostasis, and cancer invasion and metastasis of ep ithelial tissues. The administration of inhibitors for MT-SP1/matriptase may be effective to suppress the development of tumors where the enzyme may be involved. In the present study, we produced a secreted form of recombinant MT-SP1/matriptase (ekMT-SP1s) that can be activated by enterokinase in vitro and investigated the inhibitory ability of various protease inhibitors toward the recombinant enzyme. The enterokinase-treated ekMT-SP 1s (active ekMT-SP1s) cleaved various peptidyl-4-methylcoumaryl-7-amide (MCA) substrates with arginine (or lysine) residue at position P1, and the best substrate was t-butyloxycar bonyl (Boc)-Gln-Ala-Arg-MCA. The specificity for the synthetic and natural substrates of the active ekMT-SP1s was in good agreement with that of the natural enzyme. Endogenous protease inhibitors tested, except for antithrombin III, showed no or little inhibition on the cleavage of Boc-Gln-Ala-Arg-MCA by the active ekMT-SP1s. Aprotinin showed strong in hibitory activity toward the cleavage. Food-derived inhibitors, such as soybean trypsin in hibitor, Bowman-Birk inhibitor, and lima bean trypsin inhibitor inhibited it, while chicken ovomucoid did not. Synthetic inhibitors tested inhibited it, and among them, the inhibitory effect of FOY 305 was strongest. The present findings provide important information for the suppression of cancer invasion and metastasis for which MT-SP1/matriptase is responsible.

Flavor of aqueous paste ingredients deteriorates easily in the concentration process for conventional solid roux foods as well as the sterilization process at high temperatures for retort foods. On the other hand, the flavor lasts in the concentrated paste foods because the sterilization conditions are more moderate than those in retort foods. However, it is difficult to add a sufficient amount of starch into the concentrated paste foods to increase the viscosity during cooking because of the changes of the physical properties due to partial gelation caused by sterilization. We succeeded in raising the gelatinization temperature of the starch and suppressing the partial gelatinization of the starch during the pasteurization by adding dextrin into the paste foods consisting of aqueous paste ingredients and the required amount of starch. The concentrated paste foods with sufficient amount of starch produced by using this technology are easy to squeeze out the contents from the pouch and have the sufficient viscosity during cooking. This technology is contributing not only to curry but also to the development of new markets for paste-type seasonings containing starch with a fresh taste.