TY - JOUR
T1 - Role of reduced glutathione in the Δ5-3-ketosteroid isomerase reaction of liver
AU - Benson, Ann M.
AU - Talalay, Paul
PY - 1976/4/19
Y1 - 1976/4/19
N2 - Partially purified rat liver Δ5-3-ketosteroid isomerase (EC 5.3.3.1) is profoundly and specifically activated by reduced glutathione (GSH). This stimulating effect shows normal saturating kinetics, and both Km and Vmax are pH-dependent. The binding of GSH is independent of the concentration of Δ5-androstene-3,17-dione, whereas the Km for Δ5-androstene-3,17-dione is markedly reduced by saturating levels of GSH. The same catalytic site appears to isomerize both Δ5-androstene-3,17-dione and Δ5-pregnene-3,20-dione. Several steroidal inhibitors compete with Δ5-androstene-3,17-dione, whereas S-methyl-glutathione competes with GSH. This activation of Δ5-3-ketosteroid isomerase is also observed in the livers of other species (calf, guinea pig, human), and represents a hitherto unrecognized function of reduced glutathione.
AB - Partially purified rat liver Δ5-3-ketosteroid isomerase (EC 5.3.3.1) is profoundly and specifically activated by reduced glutathione (GSH). This stimulating effect shows normal saturating kinetics, and both Km and Vmax are pH-dependent. The binding of GSH is independent of the concentration of Δ5-androstene-3,17-dione, whereas the Km for Δ5-androstene-3,17-dione is markedly reduced by saturating levels of GSH. The same catalytic site appears to isomerize both Δ5-androstene-3,17-dione and Δ5-pregnene-3,20-dione. Several steroidal inhibitors compete with Δ5-androstene-3,17-dione, whereas S-methyl-glutathione competes with GSH. This activation of Δ5-3-ketosteroid isomerase is also observed in the livers of other species (calf, guinea pig, human), and represents a hitherto unrecognized function of reduced glutathione.
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U2 - 10.1016/0006-291X(76)90482-4
DO - 10.1016/0006-291X(76)90482-4
M3 - Article
C2 - 6023
AN - SCOPUS:0017062681
SN - 0006-291X
VL - 69
SP - 1073
EP - 1079
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 4
ER -