How do living cells ensure that enzymes normally convert specific substrates into products andnot vice-versa (at least instantaneously)? Why is doing so important?

ertain enzymes have been charged with digestion in the body. Lipase breaks down fats, protease breaks down proteins, cellulase breaks down fiber, amylase breaks down starch, lactase breaks down dairy, sucrase breaks down sugars, and maltase breaks down grains. The presence of digestive enzymes is of great importance to metabolic enzymes, because digestion being undertaken by a special enzyme group prevents the metabolism from fatigue. As long as digestive enzymes are present, our bodies' metabolic enzymes can carry out their own tasks alone and need not become involved in such a complex and detailed process as digestion.

For that reason a glorious mechanism operates constantly inside the human body. Whenever you see or smell something to eat, or even if you only think about it, your body triggers the production of digestive enzymes. These stimuli are of great importance, helping ready your body to deal with food before you have even taken a bite.

	1. Protease Enzyme 2. Enzyme Substrate
1. Substrate (foodstuff) 2. Products 3. Enzyme 4. Enzyme and substrate combination 5. Enzyme		1. Substrate (sucrose) 2. Enzyme (sucrase) 3. Active site 4. Fructose 5. Glucose	6. Enzyme and substrate are in a ready state. 7. Products emerge. 8. Enzyme-substrate complex 9. Substrates are converted into products. 10. Substrate binds to the enzyme.
Methods used by enzymes to break down foods Enzymes break down foodstuffs and convert them into forms that the body's cells can use. This perfect system enables all the system's needs to be met almost instantaneously.		This diagram shows the activity of the enzyme sucrase in breaking down sugar products. The new product emerging as a result of this reaction will be used in meeting the needs essential to the body's metabolism.

The process of digestion begins in the mouth, immediately after the food has been chewed. Saliva contains special enzymes, and as soon as they come into contact with food, they start breaking it down. We break down the exterior walls of foods through the chewing process. If the food is raw, the enzymes it contains are released and initiate the digestion process. Carbohydrates begin to be digested in the mouth, when the amylase in saliva breaks the molecular bonds in starch and adds to them the water molecules in saliva. The reason why you feel an increasingly sweet taste when you chew a piece of bread is that the enzymes in your saliva are converting the starch it contains into sugar.

For digestion in the mouth to take place, the necessary pH value is between 6.0 and 7.4, and the enzyme amylase functions best in that pH range. The stomach, on the other hand, is a highly acidic environment, with a pH level of between 1.0 and 3.5—which acidic conditions halt the activity of amylase. For that reason, carbohydrate digestion does not take place in the stomach.

The process of digestion begins in the mouth, then continues in the stomach and the intestines, all of which are rather different from one another in their working conditions. They therefore harbor appropriately different enzymes.

Thanks & Regards

Rinkoo Gupta

AskIITians Faculty