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'Dehydrogenases' in keywords Facet   section ZfN Section C  [X]
Facet   Publication Year 1974  [X]
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1Author    Reinhard Jeck, Christoph WoenckhausRequires cookie*
 Abstract    The coenzyme anologues [3-(2-acetylpyridinio) -propyl]-adenosine pyrophosphate and [3-(2-bromo-acetylpyridinio) -propyl] -adenosine pyrophoshate were synthesized and used for inhibition studies. While the first compound reacts as competitive inhi­ bitor against NAD+ , the latter is able to form co­ valently bound derivatives of several NAD+ -depen-dent dehydrogenases, giving informations about amino acid side chains participating in the binding of the functional coenzyme part. [3-(2-acetylpyridinio) -propyl] -adenosine pyro­ phosphate exhibits strong hypochromicity between adenine and 2-acetylpyridine ring. Cleavage of the pyrophosphate bridge increases the absorption at 261 nm up to 22% and indicates, that the stacked configuration of the molecule is preferred in aqueous solution. In enzymatic assays with YADH and GAPDH [3-(2-acetylpyridinio) -propyl] -adenosine pyrophos­ phate acts as a competitive inhibitor against NAD+ . The inhibition constants are: Xi = 1.7'10-2 M (YADH) and 4.3, 10" 4m (GAPDH) and show, that the coenzyme analogue has little affinity to the co­ enzyme binding sites. Difference spectra of the coenzyme-enzyme mixtures and the isolated com­ ponents do not show any spectral changes due to the formation of the binary complex in the case of YADH and only small effects with GAPDH. From this results it can be concluded, that the incorpora­ tion of the 2-acetylpyridinio-propyl residue into the enzymes is sterically hindered. This is also indicated by the fact, that YADH shows smaller inhibition constants with adenosine monophosphate and adeno­ sine diphosphate 1. We obtained [3-(2-bromoacetylpyridinio) -pro­ pyl]-adenosine pyrophosphate by bromination of 
  Reference    (Z. Naturforsch. 29c, 180 [1974]; received) 
  Published    1974 
  Keywords    ) N AD+ -analogues, Dehydrogenases, Inhibition, Affinity Labelling 
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 TEI-XML for    default:Reihe_C/29/ZNC-1974-29c-0180_n.pdf 
 Identifier    ZNC-1974-29c-0180_n 
 Volume    29