2 Carnosine Abstracts - FYI

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1: Mol Cell Biochem 2001 Sep;225(1-):29-34

In vitro and in vivo inhibition of muscle lipid and protein oxidation by

carnosine.

Nagasawa T, Yonekura T, Nishizawa N, Kitts DD.

Food and Health Science, Faculty of Agriculture, Iwate University, Morioka,

Japan.

Carnosine, a beta-alanyl-L-histidine dipeptide with antioxidant properties

is present at high concentrations in skeletal muscle tissue. In this study,

we report on the antioxidant activity of carnosine on muscle lipid and

protein stability from both in vitro and in vivo experiments. Carnosine

inhibited lipid peroxidation and oxidative modification of protein in

muscle tissue prepared from rat hind limb homogenates exposed to in vitro

Fenton reactant (Fe2+, H2O2)-generated free radicals. The minimum effective

concentrations of carnosine for lipid and protein oxidation were 2.5 and 1

mM, respectively. Histidine and beta-alanine, active components of

carnosine, showed no individual effect towards inhibiting either lipid or

protein oxidation. Skeletal muscle of rats fed a histidine supplemented

diet for 13 days exhibited a marked increase in carnosine content with a

concomitant reduction in muscle lipid peroxidation and protein carbonyl

content in skeletal muscle caused by subjecting rats to a

Fe-nitrilotriacetate administration treatment. This significant in vitro

result confirms the in vivo antioxidant activity of carnosine for both

lipid and protein constituents of muscle under physiological conditions.

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1: Biogerontology 2000;1(3):217-23

Carnosine reacts with protein carbonyl groups: another possible role for

the anti-ageing peptide?

Hipkiss AR, Brownson C.

Biomolecular Sciences Division, GKT School of Biomedical Sciences, King's

College London, Guy's Campus London Bridge, London EC1 1UL, UK.

alan.hipkiss@...

Carnosine (beta-alanyl-L-histidine) can delay senescence and provoke

cellular rejuvenation in cultured human fibroblasts. The mechanisms by

which such a simple molecule induces these effects is not known despite

carnosine's well documented anti-oxidant and oxygen free-radical scavenging

activities. Carbonyl groups are generated on proteins post-synthetically by

the action of reactive oxygen species and glycating agents and their

accumulation is a major biochemical manifestation of ageing. We suggest

that, in addition to the prophylactic actions of carnosine, it may also

directly participate in the inactivation/disposal of aged proteins possibly

by direct reaction with the carbonyl groups on proteins. The possible fates

of these 'carnosinylated' proteins including the formation of inert

lipofuscin, proteolysis via the proteasome system and exocytosis following

interaction with receptors are also discussed. The proposal may point to a

hitherto unrecognised mechanism by which cells/organisms normally defend

themselves against protein carbonyls.

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