A rise of Na(+)-Ca2+ exchange during ontogenic development was found in the rat brain which parallels brain maturation. Nerve endings are the main structure which contributes to the rise of the exchange activity.

• MeSH
• iontová výměna MeSH
• krysa rodu Rattus MeSH
• mikrozomy metabolismus   MeSH
• mitochondrie metabolismus   MeSH
• mozek růst a vývoj   metabolismus   MeSH
• myelinová pochva metabolismus   MeSH
• nervová zakončení metabolismus   MeSH
• sodík metabolismus   MeSH
• subcelulární frakce metabolismus   MeSH
• techniky in vitro MeSH
• vápník metabolismus   MeSH
• věkové faktory MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• sodík MeSH
• vápník MeSH

High Na+ + Ca2+ exchange rates comparable with those reported for crayfish striated muscle, rat heart and rat brain, were observed in locust striated muscle homogenates and membrane preparations. The Na(+)-Ca2+ exchange followed the 1st order kinetics with a Km value of 18 mumol.l-1 for Ca, the pH optimum was at 8, the temperature optimum at 30 degrees C, and the exchange was inhibited in the presence of sodium in the incubation medium, with a KiNa of approx. 25 mmol.l-1. The present results suggest a high Na(+)-Ca2+ exchange in locust striated muscles which operate on the calcium electrogenesis principle.

• MeSH
• aktivní transport MeSH
• iontová výměna MeSH
• kinetika MeSH
• kobylky metabolismus   MeSH
• krysa rodu Rattus MeSH
• pumpa pro výměnu sodíku a vápníku MeSH
• severní raci metabolismus   MeSH
• sodík metabolismus   MeSH
• subcelulární frakce metabolismus   MeSH
• svaly metabolismus   MeSH
• tkáňová distribuce MeSH
• transportní proteiny metabolismus   MeSH
• vápník metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• pumpa pro výměnu sodíku a vápníku MeSH
• sodík MeSH
• transportní proteiny MeSH
• vápník MeSH

• MeSH
• buněčná membrána metabolismus   MeSH
• frakcionace buněk MeSH
• iontová výměna MeSH
• liposomy MeSH
• severní raci fyziologie   MeSH
• sodík metabolismus   MeSH
• svaly metabolismus   ultrastruktura   MeSH
• techniky in vitro MeSH
• vápník metabolismus   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• liposomy MeSH
• sodík MeSH
• vápník MeSH

Na+-Ca2+ exchange rates and some physico-chemical properties of the exchanger were studied in crayfish striated muscle membranes enriched in plasma membranes prepared by differential centrifugation of muscle microsomal fraction on discontinuous sucrose density gradient. The lightest subfraction with the highest Na+, K+-ATPase and Mg2+-ATPase activities also showed the highest Na+-Ca2+ exchange rates. A number of physico-chemical characteristics of the Na+-Ca2+ exchanger found in the present experiments were similar to those reported for excitable membranes of mammals, except for the temperature optimum (20 degrees C for the crayfish).

• MeSH
• buněčná membrána účinky léků   metabolismus   MeSH
• iontová výměna MeSH
• koncentrace vodíkových iontů MeSH
• mikrozomy ultrastruktura   MeSH
• severní raci MeSH
• sodík metabolismus   MeSH
• svaly metabolismus   ultrastruktura   MeSH
• techniky in vitro MeSH
• teplota MeSH
• vápník metabolismus   MeSH
• verapamil farmakologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• sodík MeSH
• vápník MeSH
• verapamil MeSH

Effects of six thiol reagents with different physico-chemical properties were tested on the Na+-dependent 45Ca2+ transport into the rat brain microsomal membrane vesicles. The mercurials p-chlormercuribenzoate and Mersalyl effectively inhibited 45Ca2+ uptake with IC50 values in the order of 10(-4) mol X l-1 in the medium. N-ethylmaleimide and its more lipophilic analog N-(4-(2-benzoxazolyl)phenyl)maleimide were much less effective at the same concentrations. 2,2'-dithiodipyridine markedly reduced 45Ca2+ uptake already at concentrations below 10(-4) mol X l-1, whereas 5,5'-dithiobis-2-nitrobenzoate in a concentration range 10(-6)-10(-3) mol X l-1 was a weak inhibitor. Inhibitory effects of the most potent inhibitors p-chlormercuribenzoate and 2,2'-dithiodipyridine were readily reversed by 1 mmol X l-1 dithiothreitol. The results suggest that free SH groups of membrane polypeptides are involved in the functioning of the Na+-Ca2+ exchanger in the nerve tissue cell membranes.

• MeSH
• aktivní transport účinky léků   MeSH
• inbrední kmeny potkanů MeSH
• iontová výměna MeSH
• krysa rodu Rattus MeSH
• mikrozomy účinky léků   metabolismus   MeSH
• mozek účinky léků   metabolismus   MeSH
• pumpa pro výměnu sodíku a vápníku MeSH
• sodík metabolismus   MeSH
• sulfhydrylová reagencia farmakologie   MeSH
• techniky in vitro MeSH
• transportní proteiny metabolismus   MeSH
• vápník metabolismus   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• pumpa pro výměnu sodíku a vápníku MeSH
• sodík MeSH
• sulfhydrylová reagencia MeSH
• transportní proteiny MeSH
• vápník MeSH

The activity of certain key enzymes involved in glutamic acid metabolism was studied in purified brain mitochondria and in mitochondrial subfractions separated in a discontinuous 1.2--1.6 mol/l sucrose gradient. Alanine aminotransferase and glutamate dehydrogenase were found to be matrix enzymes and aspartate aminotransferase to be associated with the inner mitochondrial membranes. After the purified mitochondria had been separated into 5 subfractions, aspartate aminotransferase and NAD+-dependent isocitrate dehydrogenase were found to be bound to the lighter mitochondrial subfractions settling at the 1.4--1.5 mol/l sucrose boundary while alanine aminotransferase, 4-aminobutyrate transaminase and glutamate dehydrogenase were associated with the heavier subfractions settling below 2.4 mol/l sucrose. The highest specific activity of the given enzymes was found in the subfraction settling at the 1.4--1.5 mol/l sucrose boundary, the only exception being alanine aminotransferase activity, whose maximum was found in the subfractions settling in 1.5 and 1.6 mol/l sucrose. It was concluded that alanine aminotransferase, in conjunction with glutamate dehydrogenase, is linked to NH3 binding and to the oxidation of reduced adenine nucleotides; in addition, alanine aminotransferase is presumed to have the function of transporting glutamate from the mitochondria to the extramitochondrial space.

• MeSH
• 4-aminobutyráttransaminasa metabolismus   MeSH
• alanintransaminasa metabolismus   MeSH
• aspartátaminotransferasy metabolismus   MeSH
• frakcionace buněk MeSH
• glutamátdehydrogenasa metabolismus   MeSH
• isocitrátdehydrogenasa metabolismus   MeSH
• L-laktátdehydrogenasa metabolismus   MeSH
• mitochondrie enzymologie   MeSH
• mozková kůra enzymologie   MeSH
• skot MeSH
• zvířata MeSH
• Check Tag
• skot MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 4-aminobutyráttransaminasa MeSH
• alanintransaminasa MeSH
• aspartátaminotransferasy MeSH
• glutamátdehydrogenasa MeSH
• isocitrátdehydrogenasa MeSH
• L-laktátdehydrogenasa MeSH

• MeSH
• acetáty metabolismus   MeSH
• aminokyseliny metabolismus   MeSH
• astrocyty cytologie   MeSH
• glukosa metabolismus   MeSH
• glutamáty metabolismus   MeSH
• krysa rodu Rattus MeSH
• kyselina asparagová metabolismus   MeSH
• metabolismus lipidů MeSH
• mozková kůra cytologie   metabolismus   chirurgie   MeSH
• oxid uhličitý metabolismus   MeSH
• proteiny metabolismus   MeSH
• spotřeba kyslíku MeSH
• techniky in vitro MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• acetáty MeSH
• aminokyseliny MeSH
• glukosa MeSH
• glutamáty MeSH
• kyselina asparagová MeSH
• oxid uhličitý MeSH
• proteiny MeSH

Subcellular distribution and some physicochemical properties of alanine aminotransferase in striated muscles of the crayfish, trout, carp, frog, pigeon and rabbit were studied. It was established that: (1) Alanine aminotransferase activity in all mentioned animals occurred almost entirely in the cytosolic fraction of the muscles. Total activity and activity per mg protein were highest in crayfish and pigeon muscles and lowest in carp and trout muscles. (2) The pH optimum for the muscles of homoiotherms and poikilotherms ranged from 7.5 to 8, Km values for L-alanine were of the order 10(-3)--10(-2) M and those for alpha-ketoglutarate 10(-4) M. (3) A 10 degree C temperature increase of the incubation medium was accompanied by a 70--90% increase in activity. (4) The higher the alanine aminotransferase activity of the muscles, the relatively higher their alanine production during electrical stimulation. (5) From the above results it is concluded that alanine aminotransferase in striated muscles regulates the rate of glycolysis and energy production under conditions of anaerobiosis through the formation of alanine.

• MeSH
• alanin metabolismus   MeSH
• alanintransaminasa metabolismus   MeSH
• Columbidae MeSH
• cytosol enzymologie   MeSH
• elektrická stimulace MeSH
• frakcionace buněk MeSH
• kapři MeSH
• koncentrace vodíkových iontů MeSH
• králíci MeSH
• kyseliny ketoglutarové metabolismus   MeSH
• L-laktátdehydrogenasa metabolismus   MeSH
• laktáty metabolismus   MeSH
• pstruh MeSH
• Rana temporaria MeSH
• sarkoplazmatické retikulum enzymologie   MeSH
• severní raci MeSH
• svalové mitochondrie enzymologie   MeSH
• svaly enzymologie   MeSH
• techniky in vitro MeSH
• teplota MeSH
• zvířata MeSH
• Check Tag
• králíci MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• alanin MeSH
• alanintransaminasa MeSH
• kyseliny ketoglutarové MeSH
• L-laktátdehydrogenasa MeSH
• laktáty MeSH

• MeSH
• centrální nervový systém metabolismus   MeSH
• glutamáty biosyntéza   metabolismus   MeSH
• myši MeSH
• nervová tkáň metabolismus   MeSH
• neurotransmiterové látky fyziologie   MeSH
• ryby MeSH
• savci MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• glutamáty MeSH
• neurotransmiterové látky MeSH

1. A reversible transamination reaction between L-glutamate and pyruvate, or L-alanine and 2-oxoglutarate, takes place in the mitochondrial and cell sap fractions of rat brain. 2. The maximum rate of the transamination reaction in both subfractions was observed in the presence of a keto- substrate concentration of 2.5 mM only, but an amino- donor concentration of 20 mM. 3. The apparent Menten-Michaelis constants for pyruvate and 2-oxoglutarate were of a 10(-4) M and for L-glutamate and L-alanine of a 10(-3) M order and were approximately the same for both fractions. 4. The ratio of the initial rate of the L-alanine + 2-oxoglutarate to the L-glutamate + pyruvate transamination reaction in the cell sap and mitochondrial fractions amounted to up to 2. 5. The apparent equilibrium constant derived from the Haldane equation was 7.01 for cell sap alanine aminotransferase and 4 for the mitochondrial enzyme. 6. Increasing pyridoxal-5'-phosphate concentrations in the incubation medium were accompanied by only non-significant stimulation of alanine aminotransferase activity in the mitochondrial and cell sap fractions. 7. A comparison of the kinetic data obtained on mitochondrial and cell sap alanine aminotransferases in vitro with the actual substrate concentrations in the transamination reaction in nervous tissue in vivo indicates that the direction of the transamination reaction in situ seems to be determined simply by compartmentation and by dynamic changes in amino- and keto- substrates in the mitochondrial and cell sap spaces.

• MeSH
• alanintransaminasa metabolismus   MeSH
• cytoplazma enzymologie   metabolismus   MeSH
• glutamáty metabolismus   MeSH
• krysa rodu Rattus MeSH
• kyseliny ketoglutarové metabolismus   MeSH
• mitochondrie enzymologie   metabolismus   MeSH
• mozek enzymologie   metabolismus   ultrastruktura   MeSH
• pyridoxalfosfát farmakologie   MeSH
• pyruváty metabolismus   MeSH
• techniky in vitro MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• alanintransaminasa MeSH
• glutamáty MeSH
• kyseliny ketoglutarové MeSH
• pyridoxalfosfát MeSH
• pyruváty MeSH