To gain some insight into the mechanism of cell photostimulation by laser light, measurements were made of the rate of ADP/ATP exchange in mitochondria irradiated with the low power continuous wave Helium Neon laser (energy dose 5 Joules/om~). To do this a method has been developed to continuously monitor ATP efflux from phosphorylating mitochondria caused by externally added ADP, by photometrically following the NADP ÷ reduction which occurs in the presence of glucose, hexoklnase, glucose-6-phosphate dehydrogenase and effluxed ATP. The NADP + reduction rate shows hyperbolic dependence on ADP concentration (Km and Vmax values 8.5 +/- 0.87 ~uM and 20.7 +/- 0.49 nmoles NADP+ reduced/min x mg mitochondrial protein, respectively), and proves to measure the activity of the ADP/ATP translocator as shown by inhibition experiments using atractyloside, powerful inhibitor of this carrier. Irradiation was found to enhance the rate of ADP/ATP antiport, with externally added ADP ranging between 5 and 100 ~AM~ As a result of experiments carried out with mitochondria loaded with either or ADP, the increase in the activity of the ADP/ATP translocator is here proposed to depend on the increase in the electrochemical proton gradient which occurs owing to irradiation of mitochondria,

Increase in the ADP/ATP exchange in rat liver mitochondria irradiated in vitro by Helium-Neon laser

OSTUNI, Angela;
1988-01-01

Abstract

To gain some insight into the mechanism of cell photostimulation by laser light, measurements were made of the rate of ADP/ATP exchange in mitochondria irradiated with the low power continuous wave Helium Neon laser (energy dose 5 Joules/om~). To do this a method has been developed to continuously monitor ATP efflux from phosphorylating mitochondria caused by externally added ADP, by photometrically following the NADP ÷ reduction which occurs in the presence of glucose, hexoklnase, glucose-6-phosphate dehydrogenase and effluxed ATP. The NADP + reduction rate shows hyperbolic dependence on ADP concentration (Km and Vmax values 8.5 +/- 0.87 ~uM and 20.7 +/- 0.49 nmoles NADP+ reduced/min x mg mitochondrial protein, respectively), and proves to measure the activity of the ADP/ATP translocator as shown by inhibition experiments using atractyloside, powerful inhibitor of this carrier. Irradiation was found to enhance the rate of ADP/ATP antiport, with externally added ADP ranging between 5 and 100 ~AM~ As a result of experiments carried out with mitochondria loaded with either or ADP, the increase in the activity of the ADP/ATP translocator is here proposed to depend on the increase in the electrochemical proton gradient which occurs owing to irradiation of mitochondria,
1988
File in questo prodotto:
File Dimensione Formato  
BBRC 1988.pdf

non disponibili

Tipologia: Documento in Post-print
Licenza: DRM non definito
Dimensione 472.07 kB
Formato Adobe PDF
472.07 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11563/4840
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 129
  • ???jsp.display-item.citation.isi??? ND
social impact