Rabbit muscle lactate dehydrogenase 5; a regulatory enzyme.
نویسنده
چکیده
Lactate dehydrogenase isozyme 5 from rabbit skeletal muscle is activated by citrate, cis-aconitate, isocitrate, alpha-ketoglutarate, succinate, fumarate, malate, aspartate, and glutamate. In the presence of these activators the shape of the pyruvate saturation curve is changed from sigmoid to hyperbolic. Lactate dehydrogenase isozyme 1 from rabbit heart gives a hyperbolic pyruvate saturation curve and is not activated by these compounds. Oxalacetate is a competitive inhibitor of both isozyme 5 and isozyme 1 but at low concentration it activates the former. These results indicate that lactate dehydrogenase isozyme 5 from rabbit skeletal muscle is an allosteric protein and a regulatory enzyme, while lactate dehydrogenase isozyme 1 from rabbit heart is apparently neither.
منابع مشابه
Determination of Dissociation Constants of Coenzymes and Abortive Ternary Complexes with Rabbit Muscle Lactate Dehydrogenase from Fluorescence Measurements.
Studies on the mechanism of substrate interaction with rabbit muscle lactate dehydrogenase have recently been reported (1). These investigations, which were primarily kinetic in nature, indicated that nicotinamide adenine dinucleotide and reduced nicotinamide adenine dinucleotide must add to the enzyme before the binding of substrates pyruvate and L-lactate. It was also noted that ternary compl...
متن کاملRates of disappearance from plasma of enzymes labeled by coupling with a radioactive lodo-ester.
Lactate dehydrogenase-5 and creatine kinase from rabbit muscle were labeled by coupling with N-hydroxysuccinimidyl 3-(4'-hydroxy-[3',5'-125I]diiodophenyl)propionate. After purification, the analytical recovery of catalytically-active labeled enzyme averaged 90% for lactate dehydrogenase, 81% for creatine kinase. The labeled enzymes were injected intravenously into rabbits and disappearance from...
متن کاملTryptophan as intermediate in dehydrogenase action. 3. Evidence for complete cycle of hydrogen transfer between substrate and tryptophanyl residues in rabbit muscle lactate dehydrogenase.
Rabbit muscle lactate dehydrogenase, following equilibration at pH 10 with lactate-2-3H, was precipitated by perchloric acid or reversibly denatured by 8 M urea. The enzyme protein after either method of inactivation was found to contain about 0.5 g atom of tritium label per 132,000 g of protein. The urea-denatured, labeled enzyme, after isolation by Sephadex chromatography and partial reactiva...
متن کاملTransverse tubule Mg(2+)-ATPase of skeletal muscle. Evidence for extracellular orientation of the chicken and rabbit enzymes.
The orientation of the enzyme Mg(2+)-ATPase (EC 3.6.1.3) in the transverse tubule (TT) membranes of skeletal muscle was investigated using highly purified chicken and rabbit TT vesicles. The percentage of sealed vesicles present in these preparations averaged 88 and 78%, respectively, as calculated from the detergent-induced increase in ouabain-sensitive (Na+, K+)-ATPase activity, ATP-dependent...
متن کاملStudies on the mechanism and stereochemical properties of the oxalacetate decarboxylase activity of pyruvate kinase.
When cod fish muscle oxalacetate decarboxylase catalyzes the decarboxylation of oxalacetate in the presence of NaBH4, L-lactate results from the reduction of enzyme-bound pyruvate. However, D-lactate results when borohydride reduces the binary enzyme-pyruvate complex formed by adding pyruvate from solution, as reported by others. This observation suggests that there are alternate mechanisms for...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Science
دوره 150 3694 شماره
صفحات -
تاریخ انتشار 1965