Benders'dictionary of nutrition and food technology

21An alternative classification of the amino acids is by theirmetabolic fate; whether they can be utilised for glucose synthesisor not. Those that can give rise to glucose are termedglucogenic (or sometimes antiketogenic); those that give riseto ketones or acetyl CoA when they are metabolised are termedketogenic. Only leucine and lysine are purely ketogenic.Isoleucine, phenylalanine, tyrosine and tryptophan give rise toboth ketogenic and glucogenic fragments; the remainder arepurely glucogenic.amino acids, acidic Two of the amino acids, glutamic acid andaspartic acid, which have a carboxylic acid (—COOH) group inthe side chain.amino acids, antiketogenic See amino acids, glucogenic.amino acids, aromatic Three of the amino acids, phenylalanine,tyrosine and tryptophan, which have an aromatic group in theside chain. histidine is technically also aromatic, but is not generallygrouped with the aromatic amino acids.amino acids, basic Three of the amino acids, lysine, arginine andhistidine, which have basic groups in the side chain.amino acids, branched chain Three of the amino acids, leucine,isoleucine and valine, which have a branched aliphatic sidechain.See also maple syrup urine disease.amino acids, glucogenic Those amino acids that can give rise toglucose when they are metabolised. Sometimes known as antiketogenic,since the glucose formed in their metabolism reducethe rate of production of ketone bodies. All except lysine andleucine can be used for glucose synthesis in the body, althoughsome are also ketogenic.amino acids, ketogenic Those amino acids that give rise to ketonebodies or acetyl CoA when they are metabolised. leucine ispurely ketogenic, and isoleucine, phenylalanine, tyrosineand tryptophan give rise to both ketogenic and glucogenicfragments.amino acids, non-protein A number of amino acids occur asmetabolic intermediates, but are not involved in protein synthesisand are nutritionally unimportant, although they may occurin foods. These include ornithine and citrulline. Some inhigher plants are toxic to animals and potentially so to humans,e.g. mimosine (in alfalfa), djenkolic acid (djenkola bean),hypoglycin (unripe ackee fruit), oxalylaminoalanine (Lathyrusspp.).amino acids, sulphur Three amino acids, methionine, cysteineand cystine, contain sulphur in the side chain; although cysteine