OxyFile #130

Indian Journal of Biochemistry & Biophysics
Vol. 27, October 1990, pp. 269-274


H2O2 has a role in cellular regulation


T. Ramasarma
Department of Biochemistry
Indian Institute of Science
Bangalore 560 012


Abstract:

H2O2, in addition to producing highly reactive molecules through 
hydroxyl radicals or peroxidase action, can exert a number of direct 
effects on cells, organelles and enzymes.  The stimulations include 
glucose transport, glucose incorporation into glycogen, HMP shunt 
pathway, lipid synthesis, release of calcium from mitochondria and of 
arachidonate from phospholipids, poly ADP ribosylation, and insulin 
receptor tyrosine kinase and pyruvate dehydrogenase activities.  The 
inactivations include glycolysis, lipolysis, reacylation of 
lysophospholipids, ATP synthesis, superoxide dismutase and protein 
kinase C.  Damages to DNA and proteoglycan and general cytotoxicity 
possibly through oxygen radicals were also observed.  A whole new 
range of effects will be opened by the finding that H2O2 can act as a 
signal transducer in oxidative stress by oxidizing a dithiol protein 
to disulphide form which then activates transcription of the stress 
inducible genes.  Many of these direct effects seem to be obtained by 
dithiol-disulphide modification of proteins and their active sites, 
as part of adaptive responses in oxidative stress.