The book takes in consideration some dehydrogenases, enzymes with different functions in the cells by using different substrates, such as hydroxysteroid dehydrogenases, aldehyde dehydrogenases, glucose-6-phosphate dehydrogenase, pyruvate dehydrogenase complex, glutamate dehydrogenase, succinate dehydrogenase. They are examined from the following points of view: biochemistry, physiological functions and role in some diseases and in the development of tumours. For these reasons, the book is divided into three sections: 1. Dehydrogenases and cancer 2. Dehydrogenases and some diseases 3.
Clostridial glutamate dehydrogenase mutants, designed to accommodate
the 2¢-phosphate of disfavoured NADPH, showed the expected large speci-ficity shifts with NAD(P)H. Puzzlingly, similar assays with oxidized cofac-tors initially revealed little improvement with NADP
, although rates with
were markedly diminished.
Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: The role of glutamine synthetase, glutamate synthase and glutamate dehydrogenase in ammonia assimilation by the mycorrhizal fungus Pisolithus tinctorius...
Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp Original article đề tài: Changing electrophoretic patterns of glutamate dehydrogenases and aspartate aminotransferases in a few tree species under the influence of ectomycorrhization...
Bovine glutamate dehydrogenase is potently inhibited by zinc and the major
impact is on Vmaxsuggesting a V-type effect on catalysis or product release.
Zinc inhibition decreases as glutamate concentrations decrease suggesting a
role for subunit interactions.
Glutamate dehydrogenase (EC 188.8.131.52–4) fromPeptostreptococcus asacch-arolyticushas a strong preference for NADH over NADPH as a coenzyme,
over 1000-fold in terms ofkcat
⁄Kmvalues. Sequence alignments across the
wider family of NAD(P)-dependent dehydrogenases might suggest that this
preference is mainly due to a negatively charged glutamate at position 243
(E243) in the adenine ribose-binding pocket.
The hexameric glutamate dehydrogenase ofClostridium symbiosumhas pre-viously been shown to undergo a pH-dependent inactivating conformational
change that perturbs the environment of one or more Trp residues and is
reversed by glutamate in a highly cooperative fashion with a Hill coefficient
of almost 6.
Table 123-1 Relative Sensitivity and Specificity of Diagnostic Tests for Clostridium difficile–Associated Disease (CDAD)
Type of Test
Stool for C. difficile
Most sensitive test; specificity is ++++ if the C.
2-Oxoglutarate dehydrogenase (OGDH) is the first and rate-limiting com-ponent of the multienzyme OGDH complex (OGDHC) whose malfunction
is associated with neurodegeneration. The essential role of this complex in
the degradation of glucose and glutamate, which have specific significance
in brain, raises questions about the existence of brain-specific OGDHC iso-enzyme(s).
Aging is accompanied by gradual cellular dysfunction associated with an
accumulation of damaged proteins, particularly via oxidative processes.
This cellular dysfunction has been attributed, at least in part, to impair-ment of mitochondrial function as this organelle is both a major source of
oxidants and a target for their damaging effects, which can result in a
reduction of energy production, thereby compromising cell function.
Ammonium assimilation inEscherichia coliis regulated through multiple
mechanisms (metabolic, signal transduction leading to covalent modification,
transcription, and translation), which (in-)directly affect the activities of its
two ammonium-assimilating enzymes, i.e. glutamine synthetase (GS) and
glutamate dehydrogenase (GDH).