<prompt> Aldehyde dehydrogenase requires NAD to act. Here NAD is termed as:CofactorCoenzymeApoenzymeAbenzyme  <response>: NAD is an organic non protein poion which is required for the enzyme, so it is a coenzyme. The protein poion of holoenzyme is known as apoenzyme. The non protein poion is known as cofactor, coenzyme or prosthetic group. ADDITIONAL EDGE ON THIS TOPIC: Coenzyme Lipoic acid not a vitamin All water soluble Vitamins B - complex Vitamin C Vitamin K Nucleotides NAD NADP FMN FAD Vitamin K is the only fat soluble vitamin which acts as coenzyme SAM S - Adenosyl Methionine - Donor of methyl group PAPS Phospho Adenosyl Phospho Sulfate - Donor of Sulphate group SAM and PAPS are nucleotides but not coenzymes 