Biostimulation of Na,K-ATPase by low-energy laser irradiation (685 nm, 35 mW): comparative effects in membrane, solubilized and DPPC:DPPE-liposome reconstituted enzyme.
OBJECTIVE
The aim of the present work was to investigate the effect of low-energy laser irradiation (685 nm, 35 mW) on the ATPase activity of the different forms of the Na,K-ATPase.


METHODS
Membrane-bound and solubilized (alphabeta)(2) form of Na,K-ATPase was obtained from the dark red outer medulla of the kidney and proteoliposomes of DPPC:DPPE and Na,K-ATPase was prepared by the co-solubilization method. Irradiations were carried out at 685 nm using an InGaAIP diode laser.


RESULTS
The ATPase activity of the membrane fraction was not altered with exposition to irradiation doses between 4 and 24 J/cm(2). However, with irradiation doses ranging from 32 to 40 J/cm(2), a 28% increase on the ATPase activity was observed while when using up to 50 J/cm(2) no additional enhancement was observed. When biostimulation was done using the solubilized and purified enzyme or the DPPC:DPPE-liposome reconstituted enzyme, an increase of about 36-40% on the ATPase activity was observed using only 4-8 J/cm(2). With irradiation above these values (24 J/cm(2)) no additional increase in the activity was observed. These studies revealed that the biostimulation of ATPase activity from different forms of the Na,K-ATPase is dose dependent in different ranges of irradiation exposure. The stimulation promoted by visible laser doses was modulated and the process was reverted after 2 h for the enzyme present in the membrane and after about 5 h for the solubilized or the reconstituted in DPPC:DPPE-liposomes.
Santos
Hérica de Lima
Hde L
Universidade Federal de São João Del Rei, Departamento de Ciências Naturais, DCNAT/UFSJ, Brazil.
Rigos
Carolina Fortes
CF
Tedesco
Antonio Cláudio
AC
Ciancaglini
Pietro
P
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D004789:Enzyme Activation / Q000528:radiation effects; D007679:Kidney Medulla / Q000201:enzymology; D007700:Kinetics; D054023:Lasers, Semiconductor; D008081:Liposomes / Q000737:chemistry* / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism* / Q000528:radiation effects; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D011817:Rabbits; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism* / Q000528:radiation effects; D012995:Solubility