Mammalian Pyridoxine (Vitamin B6) Processing & Metabolism

The video tutorial explains the processing of vitamin B6, highlighting its three forms: pyridoxine, pyridoxal, and pyridoxamine. It details the conversion of these forms into the active coenzyme pyridoxal phosphate (PLP) through enzymatic pathways. The tutorial also covers the role of PLP in enzyme reactions, emphasizing its importance in human metabolism and the necessity of obtaining B6 precursors through diet.

Which of the following is NOT a form of vitamin B6 that humans can intake through diet?

• Pyridoxal Phosphate

• Pyridoxine

• Pyridoxal

• Pyridoxamine

What is the role of pyridoxal kinase in the conversion of pyridoxine?

• It oxidizes pyridoxine to pyridoxal.

• It phosphorylates pyridoxine using ATP.

• It converts pyridoxine to pyridoxamine.

• It removes the phosphate group from pyridoxine.

What is produced as a byproduct when pyridoxine is converted to pyridoxal phosphate?

• Water

• Carbon dioxide

• Oxygen

• Hydrogen peroxide

Which enzyme is responsible for converting pyridoxamine to pyridoxal phosphate?

• Pyridoxal kinase

• Pyridoxamine oxidase

• Pyridoxal phosphate phosphatase

• Pyridoxine oxidase

What is the main difference between pyridoxal and its phosphorylated form?

• Presence of an amine group

• Presence of a phosphate group

• Presence of an aldehyde group

• Presence of a hydroxyl group

How does pyridoxal phosphate attach to PLP-dependent enzymes?

• By forming a disulfide bond

• Via a lysine residue forming a Schiff base linkage

• Through ionic interactions

• Through a hydrogen bond

What happens to pyridoxal phosphate if it is not needed by the body?

• It is converted to pyridoxamine.

• It is stored in the liver.

• It is converted back to pyridoxal and excreted.

• It is used to synthesize other vitamins.