Medium-chain versus long-chain triacylglycerol emulsion hydrolysis by lipoprotein lipase and hepatic lipase: Implications for the mechanisms of lipase action

Journal Article · Tue Feb 06 00:00:00 EST 1990 · Biochemistry; (USA)

DOI:https://doi.org/10.1021/bi00457a006· OSTI ID:6699682

Deckelbaum, R J ^[1]; Hamilton, J A; Butbul, E; Gutman, A ^[2]; Moser, A ^[3]; Bengtsson-Olivecrona, G; Olivecrona, T ^[4]; Carpentier, Y A ^[5]

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1. Columbia Univ., New York, NY (USA)
2. Boston Univ. Medical Center, MA (USA)
3. Hadassah Univ. Hospital, Jerusalem (Israel)
4. Univ. of Umea (Sweden)
5. St. Pierre Univ. Hospital, Brussels (Belgium)

To explore how enzyme affinities and enzyme activities regulate hydrolysis of water-insoluble substrates, the authors compared hydrolysis of phospholipid-stabilized emulsions of medium-chain (MCT) versus long-chain triacylglycerols (LCT). Because substrate solubility at the emulsion surface might modulate rates of hydrolysis, the ability of egg yolk phosphatidylcholine to solubilize MCT was examined by NMR spectroscopy. Chemical shift measurements showed that 11 mol % of ({sup 13}C)carbonyl enriched trioctanoin was incorporated into phospholipid vesicles as a surface component. Line widths of trioctanoin surface peaks were half that of LCT, and relaxation times, T{sub 1}, were also shorter for trioctanoin, showing greater mobility for MCT in phospholipid. In assessing the effects of these differences in solubility on lipolysis, they found that both purified bovine milk lipoprotein lipase and human hepatic lipase hydrolyzed MCT at rates at least 2-fold higher than for LCT. Differences in affinity were also demonstrated in mixed incubations where increasing amounts of LCT emulsion resulted in decreased hydrolysis of MCT emulsions. These results suggest that despite lower enzyme affinity for MCT emulsions, shorter chain triacylglycerols are more readily hydrolyzed by lipoprotein and hepatic lipases than long-chain triacylglycerols because of greater MCT solubility and mobility at the emulsion-water interface.

• OSTI ID: 6699682
• Journal Information: Biochemistry; (USA), Vol. 29:5; ISSN 0006-2960
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
LIPOPROTEINS
ENZYMATIC HYDROLYSIS
PHOSPHOLIPIDS
NUCLEAR MAGNETIC RESONANCE
CARBON 13
CHEMICAL BONDS
EMULSIONS
GLYCEROL
LIPASES
SOLUBILITY
TRIGLYCERIDES
TRIOLEIN
ALCOHOLS
CARBON ISOTOPES
CARBOXYLESTERASES
CHEMICAL REACTIONS
COLLOIDS
DECOMPOSITION
DISPERSIONS
ENZYMES
ESTERASES
ESTERS
EVEN-ODD NUCLEI
HYDROLASES
HYDROLYSIS
HYDROXY COMPOUNDS
ISOTOPES
LIGHT NUCLEI
LIPIDS
LYSIS
MAGNETIC RESONANCE
NUCLEI
OILS
ORGANIC COMPOUNDS
ORGANIC PHOSPHORUS COMPOUNDS
OTHER ORGANIC COMPOUNDS
PROTEINS
RESONANCE
SOLVOLYSIS
STABLE ISOTOPES
550201* - Biochemistry- Tracer Techniques