Biosynthesis of dicarboxylic acids by carbon dioxide fixation; isolation and properties of an enzyme from pigeon liver catalyzing the reversible oxidative decarboxylation of 1-malic acid.
نویسندگان
چکیده
followed spectrophotometrically. The spectrophotometric method could not be applied to the determination of the equilibrium constant of Reaction 1 owing to interference by lactic dehydrogenase which contaminated the best preparations of the pigeon liver enzyme available (1). However, through coupling with the isocitric dehydrogenase system (Reaction 2), Reaction 3 was obtained (3). The equilibrium of this system favored the
منابع مشابه
Biosynthesis of dicarboxylic acids by carbon dioxide fixation. II. Further study of the properties of the "malic" enzyme of pigeon liver.
This enzyme is provisionally referred to as “malic” enzyme. The present paper deals with further observations on the kinetics and other properties of the purified enzyme.’ The enzyme is totally inactive in the absence of Mn++. Mg++ can replace Mn++ but is less effective. Further evidence has been obtained indicating that free oxalacetate is not an intermediate in Reaction 1 and that both Reacti...
متن کاملBiosynthesis of dicarboxylic acids by carbon dioxide fixation. IV. Isolation and properties of an adaptive "malic" enzyme from Lactobacillus arabinosus.
Reaction 1 requires DPN and manganous ions. It is specific for Imalic acid; d-malic acid is inactive. TPN cannot replace DPN. Reaction 2 requires the presence of manganous ions. The evidence presented below supports the view that Reaction 1 is a DPN-linked dismutation between Z-malate and pyruvate, resulting from the interaction of lactic dehydrogenase with a DPN-specific “malic” enzyme as show...
متن کاملBiosynthesis of dicarboxylic acids by carbon dioxide fixation. III. Enzymatic synthesis of iota-malic acid by reductive carboxylation of pyruvic acid.
A complete chemical balance which demonstrates the occurrence of Reaction 3 has now been obtained. There is no reaction in the absence of either TPN, .Zwischenferment, or “malic” enzyme. The rate of reaction is proportional to the concentration of “malic” enzyme and to the CO* tension. It is also possible to couple the isocitric dehydrogenase-oxalosuccinic carboxylase system (2) with “malic” en...
متن کاملThe enzymatic synthesis of oxalacetate from phosphoryl-enolpyruvate and carbon dioxide.
The present work is concerned with an enzyme, obtained from an acetone powder of spinach leaves, which catalyzes the carboxylation of phosphorylenolpyruvate’ to yield, under the conditions of isolation here employed, oxalacetate and inorganic phosphate. Pyruvate or pyruvate plus ATP will not substitute for PEP. Reduced triphosphopyridine nucleotide is not added to the reaction mixture and malat...
متن کاملMechanism of Pigeon Liver Malic Enzyme FORi\L4TIOS OF L-LACTATE FROM L-MALATE, AnTD EFFECTS OF ~IODIFICATIOK OF PROTEIN THIOL GROWS ON NALIC ESZTNE, OXALACETATE, AND PYRUVATE REDUCTASE -4CTIVITIES*
Crystalline pigeon liver malic enzyme (malate dehydrogenase (decarboxylating), EC 1.1.1.40) catalyzes the slow, magnesium-dependent reduction of oxalacetate and conversion of L-malate to L-lactate in the presence of TPNH and TPN, respectively, with TPN acting in a catalytic manner. Pyruvate reductase activity associated with this enzyme has a pH optimum of 6.5 to 6.8 and a Michaelis constant of...
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عنوان ژورنال:
- The Journal of biological chemistry
دوره 174 3 شماره
صفحات -
تاریخ انتشار 1948