Correct option is A
Explanation-
Analyzing the options-
Statement A - Coenzyme B12 is an organometallic compound - CORRECT
Coenzyme B12 (also called cobalamin) is indeed an organometallic compound because it contains a cobalt ion bonded to a carbon atom — a hallmark of organometallic chemistry.
Statement B - Pyridoxal phosphate is a co-factor used by many amino-transferases - CORRECT
Pyridoxal phosphate (PLP) is the active form of vitamin B6 and is a coenzyme involved in many enzyme reactions, particularly in amino acid metabolism (e.g., transamination).
Statement C- The affinity of biotin for avidin is one of the highest binding affinities known in biochemistry - CORRECT
The biotin–avidin interaction is extremely strong (dissociation constant ≈ 10⁻¹⁵ M), making it one of the strongest known non-covalent interactions in nature.
Statement D - Enzymes catalyse biochemical reactions by lowering the energy of the transition state - CORRECT
This is a fundamental principle of enzymology. Enzymes lower the activation energy (often by stabilizing the transition state), thereby accelerating the rate of biochemical reactions.
Therefore, all four statements (A, B, C, and D) are correct.
The correct answer is:
Option a : A, B, C and D
