Evidence for PQQ as cofactor in 3,4-dihydroxyphenylalanine (dopa) decarboxylase of pig kidney.
FEBS Lett
; 237(1-2): 98-102, 1988 Sep 12.
Article
em En
| MEDLINE
| ID: mdl-2844591
ABSTRACT
Pig kidney 3,4-dihydroxyphenylalanine (dopa) decarboxylase (EC 4.1.1.28) was purified to homogeneity. Treatment of the enzyme with phenylhydrazine (PH) according to a procedure developed for analysis of quinoproteins gave products which were identified as the hydrazone of pyridoxal phosphate (PLP) and the C(5)-hydrazone of pyrroloquinoline quinone (PQQ). This method failed, however, in quantifying the amounts of cofactor. Direct hydrolysis of the enzyme by refluxing with hexanol and concentrated HCl led to detachment of PQQ from the protein in a quantity of 1 PQQ per enzyme molecule. In view of the reactivity of PQQ towards amines and amino acids, we postulate that it participates as a covalently bound cofactor in the catalytic cycle of the enzyme, in interplay with PLP. Since several other enzymes have been reported to show the atypical behaviour of dopa decarboxylase, it seems that the PLP-containing group of enzymes can be subdivided into pyridoxoproteins and pyridoxo-quinoproteins.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Descarboxilases de Aminoácido-L-Aromático
/
Quinolonas
/
Dopa Descarboxilase
/
Rim
Limite:
Animals
Idioma:
En
Revista:
FEBS Lett
Ano de publicação:
1988
Tipo de documento:
Article
País de afiliação:
Holanda