All rights reserved. Terms of use. Â¨ 37 11 Thermodynamics andThermochemistry Thermodynamics is the study of heat, and how heat can be interconverted into other energyforms. In thermodynamics the system is a specific part of the universe that is being studied,often the system is a chemical reaction. The surroundings are all parts of the universe that arenot the system, typically everything outside the test tube.Â¥ An open system can exchange both energy and matter with its surroundings.
Pepsin splits proteins into water-soluble fragments called peptones. Although this ordinarily occurs in the stomach, it can be duplicated in a large reaction vessel on a commercial basis. Partial digestion by pepsin can be used in food applicationsâfor instance, in the processing of soy protein and gelatin.
8. For general digestion of proteins, suggested conditions are a 0.4% solution of pepsin in 10 mM HCl, and digestion for 30-90 minutes at 37 Â°C. Pepsin has optimal activity with native proteins at approximately pH 1.0, but with some denatured proteins the optimal activity is at approximately pH 1.5-3.5.9,10.inetics, Solubility and Solution Stability. Pepsin is soluble in deionized water at 1% (10 mg/ml) and at 0.4% (4 mg/ml) in cold 10 mM hydrochloric acid. Solutions at pH 4.4 are stable at -20 Â°C for about 2-3 months. 12 The pH optimum for activity for porcine pepsin is ~2.2.