Napoli JL, Pacia EB, Salerno GJ. Cholate effects on all-trans-retinyl palmitate hydrolysis in tissue homogenates: solubilization of multiple kidney membrane hydrolases.
Arch Biochem Biophys 1989;
274:192-9. [PMID:
2774573 DOI:
10.1016/0003-9861(89)90430-x]
[Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Retinyl ester hydrolysis was observed in the absence of cholate in homogenates of rat lung, liver, kidney, intestine, and testes. Eighty-four percent of the activity in kidney was membrane-associated. The kidney microsomal fraction contained 19% of the total activity and was the only subcellular fraction that had increased specific activity relative to the homogenate (about 1.5-fold). In contrast, the cytosol was the only fraction that was decreased in specific activity (about 3-fold). Cholate (18 mM), reportedly required to observe hydrolysis of all-trans-retinyl esters by rat liver preparations, was not obligatory for activity in kidney homogenates or microsomes. The microsomal activity was solubilized efficiently and with a twofold increase in specific activity by the synthetic detergent 1-S-octyl-beta-D-thioglucopyranoside. Gel-permeation chromatography of the solubilizate suggested that at least two pools of activity existed, with molecular weights in the ranges 70-95 and 30-40 kDa. Neither hydrolyzed cholesteryl oleate. Both were more active in hydrolyzing retinyl palmitate than trioleoylglycerol. The higher mass pool had decreased trioleoylglycerol hydrolase activity relative to the solubilizate. Anion-exchange chromatography separated the lower mass pool into two major peaks. A major peak, distinct from the two peaks observed with the lower mass pool, was observed upon anion-exchange chromatography of the higher mass pool. These data demonstrate that multiple retinyl ester hydrolases, more efficient at hydrolyzing retinyl esters than cholesteryl esters and triacylglycerol, occur in a retinoid target tissue.
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