UVA irradiation induces L-isoaspartyl formation in melanoma cell proteins.
Free Radic Biol Med
; 31(1): 1-9, 2001 Jul 01.
Article
in En
| MEDLINE
| ID: mdl-11425484
ABSTRACT
It has been reported that UVA effects are partly mediated by production of reactive oxygen species. Moreover, oxidative stress increases protein damage, involving the occurrence of isoaspartyl residues, a product of protein deamidation/isomerization reactions. This work was undertaken in order to study the effects of UVA irradiation, mediated by oxidation, on sensitive protein targets. Melanoma cells exposed to UVA rays have been chosen as a model for monitoring the occurrence of L-isoaspartyl sites. A dramatic increase of these abnormal residues, specifically recognized and methylated by the enzyme L-isoaspartate(D-aspartate) O-methyltransferase (PCMT; EC 2.1.1.77), can be detected after exposure of M14 cells to raising doses of UVA. The effect of UVA on NO and TBARS accumulation, as well as on DNA fragmentation, has also been investigated. NO formation parallels the increase in isoaspartyl formation, while lipid peroxidation occurs only at the highest UVA doses. No DNA fragmentation has been detected under the employed experimental conditions. These results, as a whole, indicate that protein damages are one of the early events on UVA-induced cell injury. The endogenous activity of PCMT remains remarkably stable under UVA treatment, suggesting that this enzyme might play a crucial role in the repair and/or disposal of damaged proteins in UVA-irradiated cells.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Aspartic Acid
/
Melanoma
/
Neoplasm Proteins
Limits:
Animals
/
Humans
Language:
En
Journal:
Free Radic Biol Med
Journal subject:
BIOQUIMICA
/
MEDICINA
Year:
2001
Document type:
Article
Affiliation country:
Italia