Nucleic acid Nucleic acid Nucleic acids are the biopolymers, or small biomolecules, essential to all known forms of life. The term "nucleic acid" is the overall name for DNA and RNA. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. If the sugar is a compound ribose, the polymer is RNA (ribonucleic acid); if the sugar is derived from ribose as deoxyribose, the polymer is DNA (deoxyribonucleic acid). Nucleic acids are the most important of all biomolecules. They are found in abundance in all living things, where they
N-Glycolylneuraminic acid N-Glycolylneuraminic acid "N"-Glycolylneuraminic acid (Neu5Gc) is a sialic acid molecule found in most non-human mammals. Humans cannot synthesize Neu5Gc because the human gene CMAH is irreversibly mutated, though it is found in apes. It is absent in human tissues because of inactivation of gene encoding CMP-N-acetylneuraminic acid hydroxylase. The gene CMAH encodes for CMP-N-acetylneuraminic acid hydroxylase, which is the enzyme responsible for CMP-Neu5Gc from CMP-N-acetylneuraminic (CMP-Neu5Ac) acid. This loss of CMAH is estimated to have occurred 2-3 million years ago, just before the emergence of the genus "Homo". Neu5Gc is closely related to the commonly known N-acetylneuraminic acid (Neu5Ac). Neu5Ac