| Abstrakt: |
Histidine decarboxylases of mammalian origin are of two main types. One of these acts not only on histidine but also on other aromatic amino acids, notably L-3,4-dihydroxyphenylalanine (DOPA) and L-5-hydroxytryptophan. A typical example of this non-specific enzyme, for which the term aromatic L-amino acid decarboxylase has been suggested1, is the histidine decarboxylase of guinea pig kidney. The other type of histidine decarboxylase, which is a specific enzyme acting only on histidine, occurs in mast cells2, in certain rapidly growing tissues3,4and is formed adaptively in the micro-circulation under suitable conditions5. Apart from their different substrate specificities the two types of histidine decarboxylase can also be distinguished by their pH optima, reaction to benzene, and particularly by their response to inhibitors2,3,6,7,8,9. |
