during late stages of erythropoiesis, cellular metabolism is remodeled so that glutamine is the precursor for 5-aminolevulinate following deamination to 2-oxoglutarate and conversion to succinyl-CoA by 2-oxoglutarate dehydrogenase without equilibration or passage through the TCA cycle. This may be facilitated by a direct interaction between 5-aminolevulinate synthase 2 and 2-oxoglutarate dehydrogenase. Succinate is not an effective precursor for heme
enzymes purified from skeletal muscle of euthermic and hibernating ground squirrels are evaluated at 5°C, 22°C, and 37 °C. The enzyme complex from hibernator muscle at all temperatures compared with euthermic controls exhibits a decreased affinity for CoA as well as reduced activation by Ca2+ ions at 5°C from both euthermic and hibernating conditions. The E1, E2 and E3 enzymes of the complex (OGDH, DLST, DLD) all show elevated phosphotyrosine content during hibernation as well as increased ADP-ribosylation and succinylation of hibernator OGDH
histone H2A.Z-bound chromatin is associated with metabolic enzymes, oxoglutarate dehydrogenase (OGDH) and acetyl-CoA acyltransferase 2 (ACAA2) in the nucleus. OGDH and ACAA2 predominantly associate with H2A.Z-occupied transcription start sites and enhancers
in Corynebacterium glutamicum, the PDH-ODH hybrid complex consists of six copies of subunit E2 in its core. E2 forms a stable complex with E3 (E2-E3 subcomplex) in vitro, hypothetically comprised of two E2 trimers and four E3 dimers. E1o exists mainly as a hexamer in solution and is ready to form an active ODH complex when mixed with the E2-E3 subcomplex. Inhibition of ODH and PDH is E1p- and E1o-dependent, respectively, actively supporting the formation Iof the hybrid complex, in which both E1p and E1o associate with a single E2-E3
isoenzymes 2-oxoglutarate dehydrogenase (OGDH) and 2-oxoadipate dehydrogenase (OADH) show a 100fold difference in their ratio in the heart and liver, but similar Michaelis saturations by 2-oxoglutarate are inherent in the enzyme preparations from these tissues. In the heart, OADH/OGDH ratio is about 0.01, and OADH possesses low-affinity sites to 2-oxoadipate. In liver preparation, OADH/OGDH ratio is about 1.6, and OADH a biphasic saturation with 2-oxoadipate
the 2-oxoadipate dehydrogenase E1a uses the dihydrolipoyl succinyltransferase (E2o) and the dihydrolipoyl dehydrogenase (E3) components of the tricarboxylic acid cycle 2-oxoglutarate dehydrogenase complex (OGDHc) for its activity. 2-Oxoglutarate and 2-oxoadipate can be oxidized by E1a, E1a displays an approximately 49fold preference in catalytic efficiency for 2-oxoadipate over 2-oxoglutarate. E1a forms the thiamidiphosphate-enamine radical from 2-oxoadipate in the oxidative half reaction, and may produce superoxide and H2O2 from decarboxylation of 2-oxoadipate in the forward physiological direction. Once assembled to complex with the same E2o and E3 components, the E1o and E1a display strikingly different regulation: both succinyl-CoA and glutaryl-CoA significantly reduced the E1o activity, but not the activity of E1a
the enzyme modulates planth growth. In reproductive tissues isoform E1-OGDH2 is important in the control of the reserves production during seed development
the OGDH complex behaves as a 2-oxoadipate dehydrogenase, in addition to its usual 2-oxoglutarate dehydrogenase activity. Human E1o by itself and when assembled into the OGDH complex can serve as a source of superoxide/H2O2 generation in mitochondria from 2-oxoadipate. A H2O2 generating activity from 2-oxoadipate of 2.668 nmol/min/mg hE1o is estimated for assembled OGDH complex and is more than 7fold higher than that with 2-oxoglutarate
two genes encode for the E1 subunit of 2-OGDH. Insertion knockout mutant lines for each of the genes exhibit substantial reduction in both respiration and CO2 assimilation rates. Mutant lines exhibit reduced levels of chlorophylls and nitrate, increased levels of sucrose, malate and fumarate and minor changes in total protein and starch levels in leaves. Absence in expression of E1-OGDH2 gene does not affect the silique length, but decreased the number of seeds per silique. In seedlings lacking only the expression of E1-OGDH2 the root growth is invariant from that of wild type seedlings
two genes encode for the E1 subunit of 2-OGDH. Insertion knockout mutant lines for each of the genes exhibit substantial reduction in both respiration and CO2 assimilation rates. Mutant lines exhibit reduced levels of chlorophylls and nitrate, increased levels of sucrose, malate and fumarate and minor changes in total protein and starch levels in leaves. E1-OGDH1 is important during early stages of seedling development, repression of the E1-OGDH1 gene leads to a significative reduction of silique length and the number of seeds per silique
in Corynebacterium glutamicum, the PDH-ODH hybrid complex consists of six copies of subunit E2 in its core. E2 forms a stable complex with E3 (E2-E3 subcomplex) in vitro, hypothetically comprised of two E2 trimers and four E3 dimers. E1o exists mainly as a hexamer in solution and is ready to form an active ODH complex when mixed with the E2-E3 subcomplex. Inhibition of ODH and PDH is E1p- and E1o-dependent, respectively, actively supporting the formation Iof the hybrid complex, in which both E1p and E1o associate with a single E2-E3