Soybeans antitrypsin

Almquist, H. J., and Merritt, J. B., 1951, Effect of soybean antitrypsin on experimental amino acid deficiency in the chick. Arch. Biochem. Biophys., 31 450-453. 

Alumot, E., and Nitsan, Z., 1961, The influence of soybean antitrypsin on the intestinal proteolysis of the chick,... 

Materials such as soybeans, lima beans, and egg whites contain natural TRY inhibitors—small polypeptides such as tti-antitrypsin (a-l-protease inhibitor) and a2-macroglob-uUn— that combine irreversibly with TRY and inactivate it by blocldng the active center. Similar nondialyzable TRY inhibitors are present in pancreatic juice, serum, and urine. These inhibitors protect plasma and other proteins against hydrolysis by TRY and other proteases if for some reason any appreciable quantity of the enzyme enters the vascular system. The absence of ai-antitrypsin is associated with an increased tendency toward panlobular emphysema in early hfe this example illustrates the effects of uninhibited proteases on organ function. 

The major plasma inhibitor of Factor XIa is Uj-antitrypsin while antithrombin III, in the presence or absence of heparin, plays a minor role in controlling this enzyme (S5). Interestingly, plant inhibitors like soybean, com, and lima bean trypsin inhibitors are able to block Factor Xlla and kallikrein but only mildly inhibit Factor XI. Thus, one can use these agents to minimize cross-reactivity in an indirect s)mthetic substrate assay for Factor XIa. 

Antienzymes polypeptides or proteins which act as enzyme inhibitors, including antibodies against antigenic proteins or coenzymes. A. include many animal and plant protease inhibitors (see Toxic proteins), such as soybean trypsin inhibitor and serum antitrypsin, which form ti t complexes with the corresponding proteases. Specific antibodies are used extensively in the purification and characterization of enzymes. 

The effects of ethanol on the conformation of aj-antitrypsin, deoxyribonuclease, pepsinogen, soybean trypsin inhibitor, and unfolded ribonucleases have been studied by c.d. spectroscopy. In the presence of 50—75 volume % ethanol, the tertiary structure is perturbed and the polypeptide chain is reorganized into new conformations with higher contents of helix and /3-structure than those in the native state. 

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