Aldehyde dehydrogenase requires NAD+ to act. Here NAD+ is termed as:

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