Plant inhibitors of proteolytic enzymes

Abstract

The presence of inhibitors of proteinases was stated in many species of plants. There are macropeptides of the molecular weight ranging from 3700 to 8000, often bound to carbohydrates. Potential sources of inhibitors of proteinases are legumes, cereals, potatoes and also some fruits. They are characterized by different activity. "Single-headed" inhibitors inhibit one type of proteolytic enzyme, when "double-headed" inhibitors, possessing two independent active sites, can inhibit several types of proteolytic enzymes at the same time. They also differ in the resistance to temperature and change of pH. The role and importance of inhibitors of proteinases is not exactly explained. They are used in the pharmaceutical, baking and beer-industry as well as in the therapy of numerous diseases.

Purification and Characterization of a Proteinase Inhibitor from Field Bean, Dolichos lablab perpureus L.

“…The FBPI exhibited an isoelectric pH of 4.3, which is comparable to those of well-characterized inhibitors from the Fabaceae suborder and a few cereals (Laskowski and Kato, 1980;Moosor et al, 1984;Norton, 1991), with the exception of peanut inhibitor, which has a pI of 8.9. In general, proteinase inhibitors are stable under usual protein denaturing conditions.…”

“…They have also been used as cancer chemopreventive agents (Kennady, 1994). They have been isolated and characterized from a wide variety of plants, most notably from legumes (Laskowski and Kato, 1980;Moosor et al, 1984;Norton, 1991; and references cited therein). Pro-1 Department of Chemistry, Bangalore University, Central College, Bangalore-560 001, India.…”

Genetic Variance of Proteolytic Activity in Alfalfa Herbage

“…and Iroquois (20.0-25.9 mg g-r) indicates that some alfalfa populations may be more responsive to selection for low proteolytic activity. This resultis not surprising since selection response for other characters such as pest resistance has been found to vary depending on the germplasm pool (Dudley et al 1963;Hill et al 1969 (Mossor et al 1984). Conse-quently, rapid lowering of silage pH through the use of bacterial inoculants or acid additives (McKersie 1985) will likely remain the most effective means, in the short term, of controlling protein degradation in alfalfa silage.…”

Research of influence of technological processing parameters of protein-fat base for supply of sportsmen on activity of protease inhibitors

“…But because of the extreme strength of the disulfide bond, considerable energy from 20 to 20 000 kcal is needed to break it (1.5 kcal is enough to break the hydrogen bond) [1]. For example, treatment of soybean seeds, even at the temperature of 232 °C for 8 minutes, does not completely destroy protease inhibitors [3].…”

“…Their charac teristic feature is the formation of stable compounds, devoid of enzymatic activity, with proteolytic enzymes. Depending on the chemical structure, localization in the plant, the level of activity, substrate specificity, protease inhibitors are grouped into three classes: Kunitz inhibitors, BaumannBirk's trypsin and chymotrypsin inhibitors, microorganism serine proteinase inhibitors that do not act on trypsin and chymotrypsin [1].…”