Question

Salivary gland enzymes liberate vitamin B12 from animal-derived proteins, allowing it to be bound by R-binder until it reaches the stomach. In the stomach, it binds with intrinsic factor and is absorbed in the ileum. What is the role of salivary gland enzymes in the absorption of vitamin B12?

1) They break down animal-derived proteins
2) They bind with intrinsic factor
3) They facilitate the absorption of vitamin B12 in the ileum
4) They liberate vitamin B12 from animal-derived proteins

Answer 1

Salivary gland enzymes play a crucial role in the absorption of vitamin B12 by liberating it from animal-derived proteins, allowing it to eventually bind with intrinsic factor and be absorbed in the ileum.

Step-by-step explanation:

The role of salivary gland enzymes, particularly in regards to the absorption of vitamin B12, is to liberate vitamin B12 from animal-derived proteins. This initial step is crucial because it allows vitamin B12 to then be bound by R-binder proteins, protecting it until it reaches the stomach. Once in the stomach, vitamin B12 is released by factors such as HCl and pepsin, and it subsequently binds with intrinsic factor, which is necessary for its absorption in the ileum. Without the actions of salivary gland enzymes at the beginning of this process, the liberation and subsequent absorption of vitamin B12 would be hindered, potentially leading to deficiencies that can affect red blood cell production and neurological function.