ISSN:
1435-1536
Keywords:
Key words Lipoprotein lipase
;
inhibition
;
phosphatidylcholine
;
sphingomyelin
;
triglyceride
;
monolayer
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
,
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract We evaluated the activation and inhibition effects of phosphatidylcholine (PC) and sphingomyelin (SM) on lipoprotein lipase (LPL) for medium or long chain-triglycerides (TG) in monolayers at the air/water interface. Monolayers of medium chain-TG, being in an expanded state at a surface pressure of 15 mN/m, showed low susceptibility to LPL in the subphase. Adding 50 mole% of PC or SM into these monolayers reduced the partial molecular area of the TG and enhanced the LPL activity. Monolayers of long chain-TG, being in a condensed state, showed high susceptibility of LPL either with or without PC. SM added to the long chain-TG monolayers, however, inhibited the LPL action. We investigated the interaction between TG and phospholipid on the basis of the collapse pressure-measurements of mixed monolayers. For medium chain-TG monolayers, PC and SM gave similar collapse pressure-composition profiles. Contrary to this, SM gave a markedly higher collapse pressure of long chain-TG than PC: SM stabilized the monolayer state of long chain-TG. These results suggested that I) orientation of the acyl chains of TG molecule in a monolayer is crucial for the LPL activity, and that II) strong interaction between SM and long chain-TG retards the substrate-transfer from the mixed monolayer to the catalytic pocket of LPL.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/s003960050052
