Hydantoin-5-propionic acid

Histamine possesses hormone activity in animals (E 3.1) and acts as a neurotransmitter (E 3.2). It is a plant feeding deterrent present, for instance, in nettle toxin (E 5.5.3). Also the alkaloid pilocarpine has strong physiological activity in vertebrates and deters potential predators (E 5.5.3). It is used as a cholinergic drug in medicine (F 2). Urocanic acid, hydantoin propionic acid, imidazoleacetic acid riboside, 1-methylhistidine, 1-methylimidazoleacetic acid and other imidazole derivatives are involved in the removal of L-histidine and histamine residues from the organism of animals. They are found in the urine. Urocanic acid is also a constituent of sweat (E 1). It is involved in the protection of skin to UV radiation (E 2.2). 

More recently Brown and Kies (S65) reported the formation from histidine and the excretion in the urine of hydantoin- propionic acid, and also its formation by liver extracts of guinea pig and the rat. The substrate for the oxidation was shown very probably to be imidazolone-propionic acid. No oxidation or formation of hydantoinpropionic acid could be demonstrated if the urocanase activity was first destroyed. The L-hydantoin-5-propionic acid was isolated by chromati raphy, and crystallized. Its identity was unequivocally established. 

Another variant has been found affecting two sisters (N5, N6). This was characterized by the urinary excretion of large quantities of hydantoin-5-propionic acid and formiminoglutamic acid, and was unresponsive to treatment with folic acid. One had retarded speech, but this was the only defect, and the other child was normal. 

Aromatic Alcohols Aromatic Amino Acids Aromatic Amino Alcohols Aromatic Thiols Aromatic Amines Aromatic Sulfoxides Mandelic Acid Analogs Aryl-Substitute Phthalides Aryl-Substituted Lactams Aryl-Substituted Succinimides Aryl-Substituted Hydantoins a-Hydroxy-a-Aryl Phosphonates Aryl Propionic Acids Phenoxy benzy 1 amine s (P-Blockers)... 

Very recently in the course of the study of the urinary products of histidine dissimilation Brown and Kies discovered L-hydantoin-5-propionic acid 255). This compound was observed in the urine of the rat and the... 

It is reasonable to assume that imidazolonepropionic acid is the substrate for the oxidation to hydantoinpropionic acid, because of its known susceptibility to oxidation. As has been mentioned above, when the oxidation was carried out chemically, no definite products could be detected. This may be because this type of oxidation goes farther than the formation of hydantoin propionate. From the data for the enzymic formation of hydantoinpropionic acid the most reasonable formulation of the reaction is the following Eq. (18.). 

Formiminoglutamic aciduria (congenital) Type r Formiminoglutamic acid, hydantoin-5-propionic acid Glutamate formiminotransferase (EC 2.1.2.5) Unproven 16.5... 

Niederwieser, A., Matasovic, A., Steinmann, B., Baerlocher, K. and Kempken, B. (1976), Hydantoin-5-propionic aciduria in folic acid non-dependent formiminoglutamic aciduria observed in two siblings. Pediatr. Res., 10,215. 

---