Effets des sels minéraux sur l'activité de la lipoprotéine lipase du lait de vache in vitro

Abstract

Listen

Translate article

Summary - Effects of mineraI salts on the actlvlty of the bovine mllk IIpoproteln lipase ln vItro. The effects of some milk constituents such as mineraI elements (Na+, W, Ca++ and Mg>+) have been studied in vitro on the mLPL (skim milk) activity and that of the purified LPL, in presence and in absence of serum lipoprotein (HDL), with a view to highlighting the incidence of these factors on the lipolysis intensity and the regulation of the enzyme lipase through these factors. The results have shown a clear similarity of the LPL behaviour of skim milk or in a purified form. The presence of HDL in the incubation medium increases seven times the mLPL activity and five times the purified LPL activity, Amongst ail mineraI constituents involved in this study, divalent ions undoubtedly hold the highest inhibitory power of the lipoprotein lipase activity. This inhibitory effect, which has been modulated by the presence of HDL, depends mainly upon the concentration and the nature of ions added to the medium, but by no means upon the ionic strengh. With 1 = 0.24, the inhibition of the LPL by CaCI2 is 75% in presence of HDL and 90% without HDL in the incubation medium. Contrastingly, with a similar ionic strengh and in presence of NaCI, this activity is subject to any modification neither in presence nor in absence of HDL in the incubation medium.