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NAD
A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)
Enzymes and Coenzymes
Biological catalysts and their cofactors.
Year introduced: 2004
Ribonucleotides
Nucleotides in which the purine or pyrimidine base is combined with ribose. (Dorland, 28th ed)
Year introduced: 1973(1971)
Purines
A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.
Purine Nucleotides
Purines attached to a RIBOSE and a phosphate that can polymerize to form DNA and RNA.
Year introduced: 1974(1972)
Nucleotides
The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King and Stansfield, A Dictionary of Genetics, 4th ed)
Nucleic Acids, Nucleotides, and Nucleosides
Complex compounds of high molecular weight occurring in living cells. These are basically of two types, ribonucleic (RNA) and deoxyribonucleic (DNA) acids, both of which consist of nucleotides (nucleoside phosphates linked together by phosphate bridges).
Year introduced: 1998
Heterocyclic Compounds, 2-Ring
A class of heterocyclic compounds that include a two-ring fused structure. Both aromatic and non-aromatic ring structures are included in this category.
Heterocyclic Compounds
Cyclic compounds that include atoms other than carbon in their ring structure.
Coenzymes
Small molecules that are required for the catalytic function of ENZYMES. Many VITAMINS are coenzymes.
Adenine Nucleotides
Heterocyclic Compounds, Fused-Ring
Multiple ring heterocyclic compounds containing two or more rings that share two atoms and one bond in common.
Year introduced: 2017