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- *******************************************************
- * DDC / GAD / HDC pyridoxal-phosphate attachment site *
- *******************************************************
-
- Three different enzymes - all pyridoxal-dependent decarboxylases - seem to
- share regions of sequence similarity [1,2], especially in the vicinity of the
- lysine residue which serves as the attachment site for the pyridoxal-phosphate
- (PLP) group. These enzymes are:
-
- - Glutamate decarboxylase (EC 4.1.1.15) (GAD). Catalyzes the decarboxylation
- of glutamate into the neurotransmitter GABA (4-aminobutanoate).
- - Histidine decarboxylase (EC 4.1.1.22) (HDC). Catalyzes the decarboxylation
- of histidine to histamine. There are two completely unrelated types of HDC:
- those that use PLP as a cofactor (found in gram-negative bacteria and
- mammals), and those that contain a covalently bound pyruvoyl residue (found
- in gram-positive bacteria).
- - Aromatic-L-amino-acid decarboxylase (EC 4.1.1.28) (DDC), also known as
- L-dopa decarboxylase or tryptophan decarboxylase. DDC catalyzes the
- decarboxylation of tryptophan to tryptamine. It also acts on 5-hydroxy-
- tryptophan and dihydroxyphenylalanine (L-dopa).
-
- -Consensus pattern: S-[LIVMFYW]-x(5)-K-[LIVMFYWG](2)-x(3)-[LIVMFYW]-x-C-x(2)-
- [LIVMFYW]-x(2)-[RK]
- [K is the pyridoxal-P attachment site]
- -Sequences known to belong to this class detected by the pattern: ALL, except
- for a probable Caenorhabditis elegans DDC.
- -Other sequence(s) detected in SWISS-PROT: NONE.
- -Last update: June 1994 / Text revised.
-
- [ 1] Jackson F.R.
- J. Mol. Evol. 31:325-329(1990).
- [ 2] Joseph D.R., Sullivan P., Wang Y.-M., Kozak C., Fenstermacher D.A.,
- Behrendsen M.E., Zahnow C.A.
- Proc. Natl. Acad. Sci. U.S.A. 87:733-737(1990).
-