Question

1. Identify and explain how certain water-soluble vitamins regulate proteins through post-translational modifications (altering the function of an existing protein by forming a covalent bond without changing its abundance).

2. Explain how vitamin C interacts with fat metabolism.

3. For carbohydrates (glycolysis/TCA), identify and discuss how vitamins are involved in procuring energy.

4. For lipids (lipolysis/β-oxidation), identify and discuss how vitamins are involved in procuring energy.

Answer 1

Water soluble vitamins

1- vitamin B

2- vitamin C

  Vitamin C and members of the vitamin B complex are water-soluble.A vitamin that can dissolve in water. Water-soluble vitamins are carried to the body's tissues but are not stored in the body. They are found in plant and animal foods or dietary supplements and must be taken in daily.

Protein Posttranslational Modifications

Proteins are the basis of cellular and physiological functioning in living organisms, and the physical and chemical properties of proteins dictate their activities and functions. The primary sequence of a protein is a main determinant of protein folding and final conformation as well as biochemical activity, stability, and half-life

  Protein PTM results from enzymatic or nonenzymatic attachment of specific chemical groups to amino acid side chains .Such modifications occur either following protein translation or concomitant with translation. PTM influences both protein structure and physiological and cellular functions.

Vitamin C and fat metabolism

Vitamin C is a cofactor in the biosynthesis of carnitine, a molecule required for the oxidation of fatty acids. A reduction in the ability to oxidize fat may contribute to the reported inverse relationship between vitamin C status and adiposity.

Glycolysis

Digestion of carbohydrates: Digestion of carbohydrates is performed by several enzymes. Starch and glycogen are broken down into glucose by amylase and maltase. Sucrose (table sugar) and lactose (milk sugar) are broken down by sucrase and lactase, respectively.

Thiamine, one of the water-soluble vitamins, is especially important in glucose metabolism.

It acts as a cofactor for enzymes that break down glucose for energy production

Lipolysis

Lipid (fat) digestion begins in the stomach with the aid of lingual lipase and gastric lipase. Lipids are digested and absorbed in the small intestine.

vitamin D stimulates lipogenesis and inhibits lipolysis by interacting with mVDR.vitamin B-6 plays in important role in lipid metabolism, such as the conversion of protein and carbohydrates to fat.