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Quaternary structure of pigeon liver malic enzyme
Author(s) -
Lee Hwei-Jen,
Chang Gu-Gang
Publication year - 1990
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(90)80837-9
Subject(s) - quaternary , protein quaternary structure , malic enzyme , enzyme , chemistry , biochemistry , biology , paleontology , dehydrogenase , protein subunit , gene
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.