Biochemistry of vitamin B6 Which compounds belong to the vitamin B6 group that serves as precursors of the active coenzyme pyridoxal-5-phosphate (PLP)? Select the most complete option.

Introduction / Context:
Vitamin B6 refers to a family of interconvertible vitamers required for numerous enzymatic reactions, especially amino acid metabolism. Knowing the members of this family is fundamental for nutrition, enzymology, and clinical biochemistry.

Given Data / Assumptions:

• Vitamin B6 includes pyridoxine (PN), pyridoxal (PL), and pyridoxamine (PM).
• The active coenzyme form is pyridoxal-5-phosphate (PLP), produced in cells from these vitamers.
• All three vitamers can be phosphorylated and interconverted.

Concept / Approach:
Identify the B6 vitamer family rather than a single molecule. Each listed compound (pyridoxal, pyridoxine, pyridoxamine) qualifies as vitamin B6 and can be converted to PLP, the universal cofactor in transamination, decarboxylation, and racemization reactions.

Step-by-Step Solution:
List recognized B6 vitamers: PN, PL, PM.Relate each to PLP via kinases and oxidases that generate PLP.Choose the option that includes all three vitamers.

Verification / Alternative check:
Textbook tables of vitamins consistently list PN, PL, and PM as B6 vitamers; clinical supplements may contain pyridoxine, which the body converts to PLP.

Why Other Options Are Wrong:
Pyridoxal alone, pyridoxine alone, or pyridoxamine alone are incomplete.PLP (option e) is the active coenzyme but the question asks which compounds belong to the B6 group (vitamers), not just the coenzyme form.

Common Pitfalls:
Confusing a single vitamer with the entire vitamin family; forgetting that the body interconverts these compounds.

Final Answer:
All of these.