Functional residues at the active site of horse liver phosphopantothenoylcysteine decarboxylase

FEBS Letters

Scandurra, R.¹  Consalvi, V.¹  Gallina, C.²  Politi, L.¹ 

[1] Departments of Biochemical Sciences University ‘La Sapienza’, Roma, Italy;Pharmaceutical Studies, University ‘La Sapienza’, Roma, Italy

关键词: Phosphopantothenoylcysteine decarboxylase;    Pyruvate;    Functional residue;    (Horse liver);    PPCDC;    4′-phosphopantothenoyl-L-cysteine decarboxylase;    PLP;    pyridoxal-5′-phosphate;    PPC;    4′-phosphopantothenoyl-L-cysteine;    Hepes;    N-hydroxyethylpiperazine-N-2-ethane sulphonate;    pMB;    p-chloromercuribenzoate;    TNBS;    2;    4;    6-trinitrobenzenesulfonic acid;    DPC;    diethylpyrocarbonate;   

DOI  :  10.1016/0014-5793(88)80729-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Horse liver phosphopantothenoylcysteine decarboxylase (EC 4.1.1.36) is rapidly inactivated by N-acetoacetylation with diketene following a pseudo-first-order kinetics: the presence of substrate quantitatively protects against this inactivation. Histidine photo-oxidation with methylene blue or rose bengal brings about the total loss of activity. These results indicate the presence of functional lysyl and histidyl groups at the active site of the enzyme. The substrate sulphydryl group is essential for enzyme activity. Enzymatic decarboxylation is proposed to result from a combined action of the keto group of the enzyme-bound pyruvate protonated by an essential histidine and a protonated amino group of a lysine.

【 授权许可】

Unknown