How does lactase work chemically

One function is to release energy through the attack of a water molecule on the adenosine triphosphate ion, better known as ATP. As this process releases energy it is downhill in terms of thermodynamics, or, as we also say, spontaneous. In principle. However, this is often a difficult reaction to carry out and it usually requires a catalyst. This is a fact we should be thankful for, as the reluctance of many compounds to add water and then split into two is what prevents our proteins from spontaneously disintegrating into free amino acids in the presence of water.

This lack of reactivity is, on the other hand, a problem for the rather large part of the population that are lactose intolerant. It has a sweet taste and is the most abundant carbohydrate in the milk of mammals.

Some mammals have more of it, notably humans with almost 7 per cent, and some have less: sea lion milk contains zero per cent lactose. The normal fate of this molecule in the body is hydrolysis. Water attacks and lactose is split into one molecule of glucose , C 6 H 12 O 6 , and one molecule of galactose, another sugar with the same formula but a slightly different arrangement of the atoms.

If this does not happen, you will get varying degrees of digestive symptoms such as flatulence, a rumbling stomach or cramps. If that is the case, you are lactose intolerant. This is not an allergy, as it does not involve our immune system. It is very important that this intolerance should not be confused with milk allergy, a reaction to certain proteins in milk, which can lead to potentially life-threatening conditions. In a way, lactose intolerance is a simple chemical problem in almost all cases, the lack of the enzyme lactase.

Despite the similar name, lactase is not a carbohydrate, but a more than times larger protein molecule, that will catalyse the hydrolysis of lactose in the stomach. Often the production of lactase diminishes in adulthood, but in regions of the world with a continuous high intake of dairy products, notably Europe, many grown-ups retain their production of this enzyme and can still digest milk.

Lactose is a small and polar molecule and is therefore water soluble but less soluble in fats. This means that dairy products such as butter and cheese, where fat gets concentrated, contain less lactose than milk.

Furthermore, when lactose is not broken down by lactase in the small intestine it can be consumed by bacteria that live in the large intestine.

Many of these bacteria use the process of sugar fermentation to produce ATP. The fermentation process produces large amounts of gaseous by-products, such as methane, carbon dioxide, and hydrogen.

This leads to gas build-up in the gut, resulting in cramping and flatulence. In the case of lactase persistence, there is a continued production of lactase at high levels throughout adulthood. Why is the production of lactase regulated in the first place? Why not just produce lactase in the enterocytes of all adult mammals? The answer is a matter of cellular energetics. Most mammals humans notwithstanding do not consume milk after they have been weaned.

Therefore, the energy invested in biosynthesizing lactase is an unnecessary expenditure. The ingested lactose is not absorbed in the small intestine, but instead is fermented by bacteria in the large intestine, producing uncomfortable volumes of carbon dioxide gas. While not all persons deficient in lactase have symptoms, those who do are considered to be lactose intolerant. Common symptoms include nausea, cramps, bloating, gas, and diarrhea, which begin about 30 minutes to 2 hours after eating or drinking foods containing lactose.

The severity of symptoms varies depending on the amount of lactose each individual can tolerate. Fortunately, lactose intolerance is relatively easy to treat by controlling the diet. No cure or treatment exists to improve the body's ability to produce lactase. Young children with lactase deficiency should not eat any foods containing lactose.

Most older children and adults need not avoid lactose completely, but individuals differ in the amounts and types of foods they can handle. Dietary control of lactose intolerance depends on each person's learning through trial and error how much lactose he or she can handle. Carbon 1 red on left is called the anomeric carbon and is the center of an acetal functional group.

A carbon that has two ether oxygens attached is an acetal. The Beta position is defined as the ether oxygen being on the same side of the ring as the C 6. In the chair structure this results in a horizontal or up projection.