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Published byJulian Robertson Modified over 8 years ago
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Group transfer enzymes
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Enzyme Coenzyme or cofactor Delivered atom or group Alcohol-dehydrogenase Catechol-O-methyltransferase Homocysteine-methyl-transferase e.g. Formyl-transferase Amino acid-transaminases Kinases NADP S-adenosyl methionine Cobalamin R-tetrahydrofolate pyridoxal phosphate Mg-ATP Hydride ion (H-atom + electron) Methyl group methyl, methylene, formyl group amino group phosphate group
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ATP and phosphoryl transfer reactions Possible structures of the Mg–ATP complex
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ATP and phosphoryl transfer reactions ATP 4– + H 2 O = H + + HPO 4 2– + ADP 3– r G 0 = 30,5 kJ/mol (i) Storage of energy for later use (creatin →creatin-phosphate) (ii) change in the conformation of a protein to control enzyme activity or transport process or in order to perform work (iii) In order to cover the energy need of the various metabolic processes, etc.
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ATP and phosphoryl transfer reactions Na +,K + pump Phosphorylation of protein side chains Glycolysis glucose + Mg-ATP → glucose-6-phosphate + Mg-ADP R-XH + Mg-ATP → R-X-PO 3 2- + Mg-ADP R-COO - + Mg-ATP → R-C(O)-O-PO 3 2- + Mg-ADP
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ATP and phosphoryl transfer reactions An example for the formation of ATP 1,3-bisphosphoglycerate3-phosphoglycerate
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ATP and phosphoryl transfer reactions A possible mechanism of the protein kinases
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ATP and phosphoryl transfer reactions A reaction catalysed by glutamine synthase
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ATP and phosporyl transfer reactions Mechanism of glutamine syntethase NH 3
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Structure of methylcobalamin (X = CH 3 ) Methylcobalamin and B 12 coenzyme
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(corrin)Co III -CH 3 (corrin)Co III + CH 3 – (corrin)Co III -CH 3 (corrin)Co II + CH 3 ● (corrin)Co III -CH 3 (corrin)Co I + CH 3 + Methylcobalamin and B 12 coenzyme
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The reaction catalysed by homocystein-methyl-transferase Methylcobalamin and B 12 coenzyme
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General mechanism of the B 12 coenzyme dependent isomerases and several representants General mechanism Enzyme Glutamate-isomerase Methylmalonyl-coenzyme A Diol-dehydratase Ethanolamine-ammonia-lyase R1HHHHR1HHHH R 2 CH(NH 2 )(COOH) H OH NH 2 R 3 H COO - H R 4 H CH 3 H X COO - C(O)-S-CoA OH Methylcobalamin and B 12 coenzyme
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B 12 coenzyme (corrin)Co II + R-CH 2 + B 12 coenzyme (corrin)Co II + R-CH 2 + Methylcobalamin and B 12 coenzyme General mechanism of the B 12 coenzyme-dependent isomerase:
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The (first step) product of the reactions catalysed by the B 12 coenzyme- dependent dehydratases gives an aldehyde by spontanaous water liberation. Methylcobalamin and B 12 coenzyme
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