acetyl coenzyme A or acetyl-CoA; a derivative of coenzyme A in which the sulfhydryl group is acetylated. Originally termed ‘active acetate’, it is an important metabolite, derived from pathways such as glycolysis, fatty-acid oxidation, and degradative metabolism of some amino acids. It is further metabolized by the tricarboxylic- acid cycle and represents a key intermediate
accession number a systematic (computer-readable) number or code that uniquely identifies an entry in a particular database. Accession numbers are assigned when entries are first added to a database and should remain static between updates, providing a reliable means of locating them in subsequent releases. For example, P02699 identifies bovine rhodopsin in the Swiss-Prot database,
acatalasemia or acatalasaemia or Takahara disease a rare, generally benign condition in which erythrocyte catalase activity is less than 1% of normal. It is sometimes associated with ulcerating lesions in the mouth. It is caused by a splice junction mutation in the catalase gene locus at 11p13.