Effect of multiple freeze-thaw cycles of cytoplasm samples on the activity of antioxidant enzymes.
BACKGROUND
In this paper the activity of cytoplasmatic antioxidant enzymes after multiple freeze-thaw cycles of samples of cytoplasm was assayed in order to characterise the limits that would be necessary to impose on experimental design.


METHODS
The activities of antioxidant enzymes in samples of rat liver cytoplasm were evaluated after 1, 2, 3, 4, 5, 10 and 15 freeze-thaw cycles. The activity of antioxidant enzymes was determined by standard methods developed for this purpose.


RESULTS
The most resistant against freeze-thaw stress was catalase; even 15 freeze-thaw cycles did not change its activity. The remaining enzymes tested revealed a significant loss in their activity after 4-5 freeze-thaw cycles. The most sensitive was glutathione S-tranferase; its activity was significantly decreased after 3 thaw cycles.


CONCLUSIONS
The data presented may be helpful in designing experiments in which assay of antioxidant enzymes is a part.
Murias
Marek
M
Department of Toxicology, Poznan University of Medical Sciences, Dojazd 30, 60-631 Poznan, Poland. amm@am.poznan.pl
Rachtan
Magdalena
M
Jodynis-Liebert
Jadwiga
J
D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D019411:Clinical Laboratory Techniques / Q000379:methods*; D003593:Cytoplasm / Q000201:enzymology*; D004795:Enzyme Stability; D005615:Freezing; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D008099:Liver / Q000166:cytology / Q000201:enzymology; D008297:Male; D010088:Oxidoreductases / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013696:Temperature
D000975:Antioxidants; D010088:Oxidoreductases; C121849:superoxide reductase; D002374:Catalase; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase