Reference

Multiple molecular forms of rat mammary glucose 6-phosphate dehydrogenase: proposed role in turnover of the enzyme

Multiple molecular forms of rat mammary glucose 6-phosphate dehydrogenase: proposed role in turnover of the enzyme. Grigor, Murray R. (Dep. Biochem., Univ. Otago, Dunedin, N. Z.). Arch. Biochem. Biophys., 229(2), 612-22 (English) 1984. CODEN: ABBIA4. ISSN: 0003-9861. DOCUMENT TYPE: Journal CA Section: 13 (Mammalian Biochemistry) Polyacrylamide gel electrophoresis showed that >80% of the total glucose 6-phosphate dehydrogenase (EC 1.1.1.49) activity of rat mammary homogenates existed as 3 dimeric forms. During lactation all 3 forms were present in equiv. amts., but 24 h after the removal of the pups to stop lactation, there was a shift to the fastest migrating form (band I). During this period the ratio of enzyme activity to tissue glutathione concn. decreased. Using partially purified prepns. of the enzyme it was shown that dithiothreitol could convert all the activity to the slowest migrating form (band III) and that diamide could reverse this change giving rise to band I only. Reduced glutathione could partially convert the enzyme to the band III form. Expts. 70-18-8 and 9001-40-5 are also in the experiment. using iodoacetic acid, iodoacetamide, p-chrloromercuribenzoate, and HgCl2 were also described. Based on these observations it is proposed that band I and band III represent fully oxidized and fully reduced forms of the enzyme, resp., and band II a partially oxidized form. The oxidized and reduced forms are catalytically equiv. However, the oxidized form is the most rapidly inactivated by a-chymotrypsin or mammary microsomes. Mammary microsomes can also catalyze the oxidn. of the enzyme. The oxidn. precedes the inactivation by microsomes and also occurs at lower microsome concns. The microsomal oxidn. of the enzyme may be the initial step in the turnover of the enzyme. .

Intrahepatic glutathione status

Intrahepatic glutathione status. Sies, Helmut; Brigelius, Regina; Akerboom, Theodorus P. M. (Inst. Physiol. Chem. I, Univ. Duesseldorf, Duesseldorf D-4000, Fed. Rep. Ger.). Funct. Glutathione: Biochem., Physiol. 70-18-8 and 27025-41-8 which are cas registry numbers are also used here., Toxicol., Clin. Aspects, [Karolinska Inst. Nobel Conf.], 5th, Meeting Date 1982, 51-64. Edited by: Larsson, Agne. Raven: New York, N. Y. (English) 1983. CODEN: 50PWA4. DOCUMENT TYPE: Conference CA Section: 13 (Mammalian Biochemistry) The status of cellular protein mixed disulfides and the relationship between intracellular GSH contents and biliary GSSG efflux in rat liver is discussed. The response of these parameters to oxidative stress is presented. .