Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.6.3.1 (Mg2+-ATPase)
 1,484 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Galactosaemia is an inborn error of metabolism characterized by irreversible damage to neural tissue. To evaluate whether galactose metabolic disorders, (e.g. classical galactosaemia, galactokinase deficiency galactosaemia), is implicated for alterations of brain Mg2+-ATPase activity, various concentrations (1-16 mM) of galactose, galactose-1-phosphate, galactitol, glucose-1-phosphate or glucose were preincubated with whole brain homogenates of suckling rats at 37 degrees for 1 hr. Mg2+-ATPase activities were determined according to Bowler & Tirri's (1974). Galactose-1-phosphate or glucose-1-phosphate excessively activated the brain Mg2+-ATPase in a concentration-dependent way. Additionally, galactitol, galactose or glucose stimulated the enzyme up to 35-45% (P < 0.001) at concentrations >4 mM. A mixture of galactose-1-phosphate (2 mM), glactitol (2 mM) and galactose (4 mM), concentrations commonly found in blood and brain of untreated patients with classical galactosaemia, resulted in a 500% enzyme activation (P < 0.001) as compared to control. Moreover, a mixture of galactitol (2 mM) and galactose (1 mM), concentrations measured in patients with galactokinase deficiency, caused an enzyme stimulation (35%, P < 0.001). These findings suggest: a) The great Mg2+-ATPase activation by galactose-1-phosphate or glucose-1-phosphate may be due to the epimer of galactose and the presence of phosphorus. b) The brain Mg2+-ATPase stimulation by galactose and its derivatives could be toxic by modulating the Mg2+ concentration, the ATP availability, the activity of other ATP- and Mg2+-dependent enzymes as well as the rates of protein synthesis and cell growth.
 ...
PMID:The in vitro effects of galactose and its derivatives on rat brain Mg2+-ATPase activity. 1257 32

The aim of this study was to evaluate whether the addition of the antioxidants L-cysteine (Cys) or the reduced glutathione (GSH) could reverse the alterations of brain total antioxidant status (TAS) and the modulated activities of the enzymes (Na+,K+)-ATPase, and Mg2+-ATPase in adult or aged rat brain homogenates induced by galactosemia in vitro. Mixture A [mix. A: galactose-1-phosphate (Gal-1-P, 2 mM) plus galactitol (Galtol, 2 mM) plus galactose (Gal, 4 mM) = classical galactosemia] or mixture B [mix. B: Galtol (2 mM) plus Gal (1 mM) = galactokinase deficiency galactosemia] were preincubated in the presence or absence of Cys (0.83 mM) or GSH (0.83 mM) with adult or aged brain homogenates at 37 degrees C for 1 h. TAS and the enzyme activities were determined spectrophotometrically. Mix. A or mix. B preincubation with the adult brain resulted in a significant (Na+,K+)-ATPase inhibition (-30%) and a Mg2+-ATPase stimulation (+300% and +33%, respectively), whereas lower modifications of the enzyme activities (p < 0.001) were found in the aged brain. Gal mixtures decreased TAS by 40% (p < 0.001) and by 20% (p < 0.01) in adult and aged samples, respectively. The antioxidants significantly increased TAS resulting in the reversion of (Na+,K+)-ATPase inhibition and Mg2+-ATPase stimulation by mix. B only. The inhibitory effect of Gal and its derivatives on brain (Na+,K+)-ATPase and their stimulatory effect on Mg2+-ATPase are being decreased with age, probably due to the producion of free radicals. Cys and GSH increased TAS resulting in a reversion of the inhibited (Na+,K+)-ATPase in both models of the in vitro galactosemia and the stimulated Mg2+-ATPase in galactokinase deficiency galactosemia only.
 ...
PMID:The protective effect of L-cysteine and glutathione on the adult and aged rat brain (Na+,K+)-ATPase and Mg2+-ATPase activities in galactosemia in vitro. 1591 54