Kinetics of 2-monoacylglycerol acyl migration in model chylomicra.
In the metabolism of triacylglycerol (TG)-rich lipoproteins, 2-monoacylglycerols (2-MG) are produced by lipoprotein lipase (LPL) hydrolysis of TG. The metabolic fate of 2-MG is not known with certainty. 2-MG that accumulate on the chylomicra surface have been proposed to isomerize spontaneously to 1(3)-MG, which are then hydrolyzed by LPL to free fatty acids and glycerol. In this study the rate and the effect of acyl chain saturation on the spontaneous acyl migration of 2-MG in in vitro model chylomicra emulsions were determined. After 1 h of incubation at 37 degrees C, less than 20% of 2-monoolein (2-MO) or 2-monopalmitin (2-MP) spontaneously isomerized to 1(3)-MO or 1(3)-MP, respectively. Accordingly, it was concluded that spontaneous isomerization of 2-MG is not the major mechanism for 2-MG metabolism post-TG hydrolysis in chylomicra. Isomerization rates, expressed as decrease in percentage of 2-MG remaining per hour, were -5.12 and -5.86 in water, and -0.43 and -0.41 in hexane for 2-MO and 2-MP, respectively. There was no significant difference between the isomerization rates of 2-MO and 2-MP. Thus, in the present study, saturation of the MG acyl chain did not influence spontaneous acyl migration in either water or hexane, but isomerization of 2-MG was faster in water than in hexane.
Lyubachevskaya
G
G
Department of Nutrition and Food Science, University of Maryland, College Park 20742, USA.
Boyle-Roden
E
E
D001692:Biological Transport; D002849:Chromatography, Gas; D002914:Chylomicrons / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D005989:Glycerides / Q000737:chemistry / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism; D006586:Hexanes / Q000737:chemistry; D006868:Hydrolysis; D007536:Isomerism; D007700:Kinetics; D008071:Lipoprotein Lipase / Q000378:metabolism; D013010:Sonication; D013696:Temperature; D013997:Time Factors; D014280:Triglycerides / Q000378:metabolism; D014867:Water / Q000737:chemistry
D002914:Chylomicrons; D005227:Fatty Acids; D005989:Glycerides; D006586:Hexanes; D014280:Triglycerides; D014867:Water; C005953:monoolein; D008071:Lipoprotein Lipase; D005990:Glycerol; C027735:palmitoyl glycerol