table 8-2 Some Coenzymes That Serve as Transient Carriers of Specific Atoms or Functional groups* Examples of chemical Dietary precursor in Coenzyme groups transferred mammaLs Biocytin Biotin Coenzyme A Acyl groups Pantothenic acid and other compounds 5-Deoxyadenosylcobalamin H atoms and Vitamin B 12 coenzyme B12) alkyl groups Flavin adenine dinucleotide Electrons Riboflavin(vitamin B2) Lipoate Electrons and Not required in diet acyl groups Nicotinamide adenine Hydride ion(: H Nicotinic acid(niacin) dinucleotide yridoxal phosphate Amino groups Pyridoxine (vitamin B6) Tetrahydrofolate One-carbon groups Folate Thiamine pyrophosphate Aldehydes Thiamine (vitamin B,) "The structure and mode of action of these coenzymes are described in Part Ill of this book