Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.3.5.1 (succinate dehydrogenase)
 8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Lutein and zeaxanthin are dihydroxy xanthophylls that are produced from their corresponding carotene precursors by the action of beta- and epsilon -ring carotenoid hydroxylases. Two genes that encode beta-ring hydroxylases (beta-hydroxylases 1 and 2) have been identified in the Arabidopsis genome and are highly active toward beta-rings but only weakly active toward epsilon -rings. A third distinct activity required for epsilon -ring hydroxylation has been defined by mutation of the LUTEIN1 (LUT1) locus, but LUT1 has not yet been cloned. To address the individual and overlapping functions of the three Arabidopsis carotenoid hydroxylase activities in vivo, T-DNA knockout mutants corresponding to beta-hydroxylases 1 and 2 (b1 and b2, respectively) were isolated and all possible hydroxylase mutant combinations were generated. beta-Hydroxylase single mutants do not exhibit obvious growth defects and have limited impact on carotenoid composition relative to the wild type, suggesting that the encoded proteins have a significant degree of functional redundancy in vivo. Surprisingly, the b1 b2 double mutant, which lacks both known beta-hydroxylase enzymes, still contains significant levels of beta-carotene-derived xanthophylls, suggesting that additional beta-ring hydroxylation activity exists in vivo. The phenotype of double and triple hydroxylase mutants indicates that at least a portion of this activity resides in the LUT1 gene product. Despite the severe reduction of beta-carotene-derived xanthophylls (up to 90% in the lut1 b1 b2 triple mutant), the double and triple hydroxylase mutants still contain at least 50% of the wild-type amount of hydroxylated beta-rings. This finding suggests that it is the presence of minimal amounts of hydroxylated beta-rings, rather than minimal amounts of specific beta-carotene-derived xanthophylls, that are essential for light-harvesting complex II assembly and function in vivo. The carotenoid profiles in wild-type seeds and the effect of single and multiple hydroxylase mutations are distinct from those in photosynthetic tissues, indicating that the activities of each gene product differ in the two tissues. Overall, the hydroxylase mutants provide insight into the unexpected overlapping activity of carotenoid hydroxylases in vivo.
 ...
PMID:Functional analysis of beta- and epsilon-ring carotenoid hydroxylases in Arabidopsis. 1278 26

3-Nitropropionic acid (3-NP) induces cellular energy deficit and oxidative stress-related neurotoxicity via an irreversible inhibition of mitochondrial complex II enzyme, succinate dehydrogenase. Huntington's disease (HD) is a neurological disorder characterized by cognitive and motor dysfunctions. Lutein is a well-known antioxidant used in the management of oxidative stress related diseases. Clinical trials have supported the beneficial effect of lutein in Alzheimer's disease. The present study was designed to explore possible neuroprotective effects of lutein on 3-NP-induced mitochondrial dysfunction and oxidative stress. Systemic administration of 3-NP (25 mg/kg intraperitoneally [i.p.] for 4 consecutive days) caused loss of body weight and neurobehavioral deficits by hind-limb impairment (Narrow Beam test), motor coordination (locomotor activity) and memory dysfunction (Morris water maze and Elevated Plus maze performance). Biochemical analysis revealed significant increase in lipid peroxidation, nitrite concentration, reduced gutathione levels, and acetyl cholinesterase levels and depleted catalase activities in rat brain. The activities of mitochondrial complexes (I, II, IV, and MTT assay) were found to be significantly lowered in brain mitochondria. Daily lutein (50 or 100 mg/kg orally [p.o.]) administration for 14 days significantly improved body weight, neurobehavioral alterations and attenuated oxidative stress and improved mitochondrial enzymes complex activities of rat brain. Histopathological examination further affirmed the neuroprotective effect of lutein on 3-NP induced pathological lesions. The present study indicates that lutein is a promising candidate for the management of HD and related conditions.
 ...
PMID:Neuroprotective effect of lutein against 3-nitropropionic acid-induced Huntington's disease-like symptoms: possible behavioral, biochemical, and cellular alterations. 2413 68