Quaternary structure of pigeon liver malic enzyme

FEBS Letters

Chang, Gu-Gang¹  Lee, Hwei-Jen¹ 

[1] Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, Republic of China

关键词: Quaternary structure;    Ligand binding;    NADP analog;    Asymmetric model;    Malic enzyme;    Pigeon liver;    AADP+ 3-aminopyridine adenine dinucleotide phosphate;    ϵNADP +;    nicotinamide;    l;    N 6-ethenoadenine dinucleotide phosphate;   

DOI  :  10.1016/0014-5793(90)80837-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Pigeon liver malic enzyme (EC 1.1.1.40) has a double dimer quaternary structure. The NADP⁺ analogs, aminopyridine adenine dinucleotide phosphate and nicotinamide-1.N ⁶-ethenoadenosine dinucleotide phosphate, bind to the enzyme anti-cooperatively. In the presence of non-cooperative competing ligand NADP⁺ the binding parameter Hill coefficients of these analogues changed very little. Binding of L-malate with enzyme-AADP⁺ complex first enhanced then reduced the nucleotide fluorescence. Two L-malate binding sites, with K _d values of 23–30 and 270–400 μM, respectively, for the tight and weak binding sites were postulated. A hybrid model between the sequential and pre-existing asymmetrical models was proposed for the pigeon liver malic enzyme.

【 授权许可】

Unknown