Enzyme inhibitors in foods

Friedman, M. (Editor). Nutritional and Toxicological Significance of Enzyme Inhibitors in Foods. Adv. Exp. Med. Biol. Plenum New York 1986 Vol. 199, 570 pages. 

Bessho, H., and Kurosawa, S., 1967, Enzyme inhibitor in foods. III. Effect of cooking on the amylase inhibitor in flour. Eiyo To Shokuryo 20 317-319 Chem. Abstr., 68 113474e. 

Friedman, M., Grosjean, 0. K., and Zahnley, J. C. (1982a). Effect of disulfide bond modification on the structure and activities of enzyme inhibitors. In "Food Protein Deterioration. Mechanisms and Functionality T J P Cherry, ed.. Am. Chem. Soc. 

Gross pathological lesions are almost invariably preceded by biochemical lesions, and hence derangement or overloading of biochemical processes may have important consequences w ith respect to food safety. This concept is discussed in relation to congenital metabolic disorders, enzyme inhibitors in food and drugs, and dose-response characteristics. 

Considerable interest has recently been aroused by reports that patients treated with monoamine oxidtise inhibitors may suffer severe hypertensive attacks after taking certain foods, notably cheese - , beans and extracts of yeast . Some of these attacks have proved fatal. The hypertensive crises arise as a result of pressor substances in the offending foods (such as tyramine in cheese) which are absorbed unchanged into the blood stream when intestinal and liver monoamine oxidase is inhibited . Some of the inhibitors (tranylcypromine is an example) also have sympathomimetic actions which will contribute to the hypertensive effect. The administration of sympathomimetic substances—such as adrenaline in a local anaesthetic—to patients treated with monoamine oxidase inhibitor also creates a dangerous situation. The possibility of hypertensive crises clearly constitutes a serious hazard of therapy with these enzyme inhibitors. In many instances their limited effectiveness would not justify the exposure of patients to these hazards. 

The nutritional importance of the protease inhibitors in major foods is reasonably clear. It is known that raw soybean flour inhibits growth in rats, chickens and some other monogastric animals (118) and death can result (119). It is also known that the presence of soybean inhibitor in the small intestine increases the secretion of a hormonal pancreozymic-like substance that markedly stimulates external secretion by the pancreas (120). The presence of active proteolytic enzyme inhibitors in the small intestine increases the production and secretion of proteolytic enzymes by the pancreas, presumably to compensate for their loss by complexation (121-123). This results in hyperplasia of some of the pancreatic cells and enlargement of the pancreas. 

Wako, Y., Abe, Y., Handa, T., and Ishikawa, S. (1999). Angiotensin 1-converting enzyme inhibitors in fish water soluble protein hydrolyzates prepared by bioreactor. Food Sci. Technol. Res. 5,378-380. 

Enzymatic food analysis involves the determination of food constituents, which can be both substrates or inhibitors of enzymes, and the determination of enzyme activity in food. 

ZAHNLEY J c (1984) Stability of enzyme inhibitors and lectins in foods and the influence of specific binding interactions. Adv Exp Med Biol. 177 333-65. 

MAO-inhibitors are chemical compounds whose activity in the body slows down or interferes with Mono Amine Oxidase, an enzyme system that oxidizes many compounds in foods and drugs into harmless byproducts. In the presence of MAO-inhibitors, compounds that would normally be metabolized into inactive by-products instead have the duration of their physiological and psychological activity extended. 

Mollusks along with the crustaceans are also widely sought to participate in the world s consumption of marine food. Fermented marine food sauces such as blue mussel sauce and oyster sauce possess bioactive peptides which play a major role as Angiotensin I converting enzyme inhibitors that indirectly suppress hypertension (Wijesekara and Kim, 2010). Hence, the mollusk-derived proteins and other macromolecules are highly valuable to indicate these organisms as medicinally valuable food sources. 

Chandrasekher, G., Raju, D. S., and Pattabiraman, T. N. (1981). Natural plant enzyme inhibitors, a-amylase inhibitors in millets. ]. Sci. Food Agriculture. 32, 9-16. 

MAO-A (isoform A) is the amine oxidase primarily responsible for norepinephrine, serotonin, and tyramine metabolism. MAO-B is more selective for dopamine. The irreversible inhibitors available in the USA are nonselective and block both forms of the enzyme. Irreversible block of MAO, characteristic of the older MAO inhibitors, allows significant accumulation of tyramine and loss of the first-pass metabolism that protects against tyramine in foods. As a result, the irreversible MAO inhibitors are subject to a very high risk of hypertensive reactions to tyramine ingested in food. 

Omeprazole itself is not the active inhibitor of the H+, K+-ATPase, however. Rather, the transformation of omeprazole in acid is required to inhibit the H+, K+-ATPase in vitro and in vivo, whereas intact omeprazole is devoid of inhibitory action. Isolated H+, K+-ATPase is blocked by omeprazole only after the pretreatment of omeprazole with acid. Conversely, neutralization of the acid-secretory canaliculi of isolated gastric gland and parietal cell preparations by permeable buffers, which blocks the acid-catalyzed transformation of omeprazole, prevents inhibition of the enzyme. Furthermore, in-vivo blockade of acid secretion using an H2-receptor antagonist prior to omeprazole administration decreases the inhibitory potency of omeprazole, whereas the stimulation of acid secretion (e.g., by food intake) increases the potency. 

---