CRYSTALLINE SOYBEAN TRYPSIN INHIBITOR : II. GENERAL PROPERTIES
A study has been made of the general properties of crystalline soybean trypsin inhibitor. The soy inhibitor is a stable protein of the globulin type of a molecular weight of about 24,000. Its isoelectric point is at pH 4.5. It inhibits the proteolytic action approximately of an equal weight of crystalline trypsin by combining with trypsin to form a stable compound. Chymotrypsin is only slightly inhibited by soy inhibitor. The reaction between chymotrypsin and the soy inhibitor consists in the formation of a reversibly dissociable compound.The inhibitor has no effect on pepsin.The inhibiting action of the soybean inhibitor is associated with the native state of the protein molecule. Denaturation of the soy protein by heat or acid or alkali brings about a proportional decrease in its inhibiting action on trypsin. Reversal of denaturation results in a proportional gain in the inhibiting activity.
Crystalline soy protein when denatured is readily digestible by pepsin, and less readily by chymotrypsin and by trypsin. Methods are given for measuring trypsin and inhibitor activity and also protein concentration with the aid of spectrophotometric density measurements at 280 mµ. 
Activation of influenza A viruses by trypsin treatment
A comparative analysis has been carried out on the infectivity of virus of several influenza A strains grown in different host systems. Strains A/swine/Shope/31 (Hsw1N1), A/PR/8/34 (HON1), A/FM/1 (H1N1), A/Singapore/1/57 (H2N2), A/equine/Miami/1/63 (Heq2Neq2), and A/chick/Germany/49 (Hav2Neq1) exhibit host-dependent differences in infectivity. Virions grown in embryonated eggs and cultures of chorioallantoic membrane cells are highly infectious, whereas virions grown in cultures of chick embryo cells have a low infectivity that significantly increases after treatment in vitro with trypsin. In contrast, fowl plague viruses do not show host-dependent variations in infectivity. Virions grown in all host systems tested are highly infectious, and the infectivity of virions grown in chick embryo cells cannot be enhanced by trypsin treatment. 
A MODIFIED SPECTROPHOTOMETRIC DETERMINATION OF CHYMOTRYPSIN, TRYPSIN, AND THROMBIN
The spectrophotometric procedure proposed by Schwert and Takenaka for the assay of chymotrypsin and trypsin has been modified and extended to include the application to N-benzoyl-L-tyrosine ethyl ester and α-p-toluenesulphonyl-L-arginine methyl ester. The greater degree of sensitivity and specificity thus achieved permits the determination of traces of chymotrypsin in the presence of relatively large amounts of trypsin and vice versa. A similar spectrophotometric procedure for the assay of thrombin is described. 
Characterization of Trypsin-Like Serine Protease from Lethocerus indicus Salivary Venom and its Cytotoxic Effect against Human Epidermoid Carcinoma Cell, A431
Objective: Lethocerus indicus salivary venom characterization and evaluation of extracellular degradation activity and cytotoxic effect against native human collagen type 1 and epidermoid carcinoma cell, A431. Method: Salivary venom extract was collected from adult insects by injecting 2% pilocarpine of 50 µml. Enzyme presence was detected by the apiZYM assay. The proteolytic activity was tested by the photometric and zymogram methods using specific fluorescent substrates and inhibitors. The cytotoxic activity was determined by the MTT assay and Trypan blue exclusion method. Apoptosis induction was observed using AO/EB staining solution. Digestion of extracellular matrix protein was detected against native human type I collagen. Result: L. indicus salivary venom presents amylases, proteases, carbohydrases, phosphatases and lipases. Among them, protease enzyme showed highest composition. The highest rate of proteolytic activity observed at pH 8 in 35ºC (100 %). Serine proteases present predominantly in salivary venom. Cysteine and metalloproteases are also detected. The activation energy of salivary venom is 49.86 kJ. Use of serine inhibitor, PMSF inhibited 92.77% which indicated that the maximum activity was due to serine protease. Detection of trypsin-like protease was confirmed by using PMSF and TLCK with specific substrate, BApNA. It shows significant inhibitions, 82% and 78% respectively suggesting maximum influence in salivary venom. Degradation of the fibrillar native state collagen Type I into 8 smaller peptide bands showed it importance in medical application. IC50 concentration of venom that induces cytotoxicity in epidermoid carcinoma cells, A431was 2.3 µg/ml only. It gives prominent apoptotic features such as cytoplasmic membrane blebbing, nuclear contraction, nuclear fragmentation and contact inhibition. 
Anti-Coccidiosis Potential of Autoclaveable Antimicrobial Peptides from Xenorhabdus budapestensis Resistant to Proteolytic (Pepsin, Trypsin) Digestion Based on In vitro Studies
Aims: To elucidate the anticoccidial potential of antimicrobial peptides from Xenorhabdus budapestensison both causative pathogens (prokaryotic Clostridium perfringens and eukaryotic Eimeria tenella).
Objectives: (1) To establish if the antimicrobial compounds of the cell-free culture media (CFCM) of the entomopathogenic symbiotic bacterium species, X. budapestensis DSM 16342 (EMA) and X. szentirmaii DSM 16338 (EMC) were active against 13 independent pathogenic isolates of Clostridium perfringens in vitro; (2) To create a sterile, autoclaved, bio-preparation called “XENOFOOD”, for future in vivo feeding studies, aimed at determining the efficacy, and side-effects, of EMA and EMC on C. perfringens in chickens.
Study Design: Clostridium perfringens samples (LH-1-LH24) were collected from chickens and turkeys, and were deposited in the frozen stock collection of Department of Microbiology and Infectious Diseases, Faculty of Veterinary Science, Szent István University, Budapest, Hungary, where the in vitro assays were carried out on 13 of these isolates. 
 Kunitz, M.T., 1947. Crystalline soybean trypsin inhibitor: II. General properties. The Journal of General Physiology, 30(4), pp.291-310.
 Klenk, H.D., Rott, R., Orlich, M. and Blödorn, J., 1975. Activation of influenza A viruses by trypsin treatment. Virology, 68(2), pp.426-439.
 Hummel, B.C., 1959. A modified spectrophotometric determination of chymotrypsin, trypsin, and thrombin. Canadian journal of biochemistry and physiology, 37(12), pp.1393-1399.
 Debaraj, H., Shantibala, T., K. Lokeshwari, R. and Giri, S. (2014) “Characterization of Trypsin-Like Serine Protease from Lethocerus indicus Salivary Venom and its Cytotoxic Effect against Human Epidermoid Carcinoma Cell, A431”, Biotechnology Journal International, 4(9), pp. 990-1010. doi: 10.9734/BBJ/2014/12217.
 Fodor, A., Makrai, L., Fodor, L., Venekei, I., Husvéth, F., Pál, L., Molnár, A., Dublecz, K., Pintér, C., Józsa, S. and Klein, M. (2018) “Anti-Coccidiosis Potential of Autoclaveable Antimicrobial Peptides from Xenorhabdus budapestensis Resistant to Proteolytic (Pepsin, Trypsin) Digestion Based on In vitro Studies”, Microbiology Research Journal International, 22(4), pp. 1-17. doi: 10.9734/MRJI/2017/38516.