Methämoglobinbildung in Erythrocyten durch Peroxideinwirkung. Versuche zur Beurteilung der Schutzfunktion von Katalase und Glutathionperoxidase
1964; Wiley; Volume: 47; Issue: 6 Linguagem: Inglês
10.1002/hlca.19640470606
ISSN1522-2675
AutoresH. Aebi, J. P. Heiniger, Emmanuelle Lauber,
Tópico(s)Neonatal Health and Biochemistry
ResumoAbstract The rate of methaemoglobin formation induced by small amounts of H 2 O 2 , a) generated enzymatically, or (b) added by diffusion as vapour, has been investigated in suspensions of normal and acatalasic red cells. At low rates of H 2 O 2 ‐generation ( i . e . 10 −10 −10 −9 moles H 2 O 2 /mg Hgb/min) removal of H 2 O 2 is mainly due to glutathione peroxidase activity, whereas at higher rates ( i . e . 10 −9 −10 −7 moles H 2 O 2 /mg Hgb/min) catalase activity is responsible for haemoglobin protection. Under the latter experimental conditions the yield of methaemoglobin formcd depends mainly on red cell catalase activity. The existence of a lag‐phase in methaemoglobin formation and measurements of reduced glutathione concentration suggest that catalase and haemoglobin compete for excess H 2 O 2 only after the intracellular supply of reduced glutathione has been exhausted and the H 2 O 2 concentration in the cells has passed a critical level of than 7 · 10 −6 M H 2 O 2 .
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