The identity of vitamin A esterase activity of rat pancreatic juice

Erlanson, Charlotte; Borgström, Bengt

doi:10.1016/0005-2744(68)90059-4

Cited by 44 publications

(21 citation statements)

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“…However, studies in CEH-deficient mice showed that this enzyme was not significantly involved in the hydrolysis of retinyl esters in vivo [18,19]. Since some studies showed that the LP could hydrolyse retinyl palmitate in vitro [18,20,21,22] and as the CEH was not involved, it is assumed that the luminal hydrolysis of retinyl esters is achieved by the LP, together with the pancreatic lipase-related protein 2 [22]. The enzymes described above are all good candidates for the hydrolysis of esters of carotenoids.…”

Section: Overview Of Vitamin a And Carotenoid Fate During The Digementioning

confidence: 99%

Absorption of Vitamin A and Carotenoids by the Enterocyte: Focus on Transport Proteins

2013

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Vitamin A deficiency is a public health problem in most developing countries, especially in children and pregnant women. It is thus a priority in health policy to improve preformed vitamin A and/or provitamin A carotenoid status in these individuals. A more accurate understanding of the molecular mechanisms of intestinal vitamin A absorption is a key step in this direction. It was long thought that β-carotene (the main provitamin A carotenoid in human diet), and thus all carotenoids, were absorbed by a passive diffusion process, and that preformed vitamin A (retinol) absorption occurred via an unidentified energy-dependent transporter. The discovery of proteins able to facilitate carotenoid uptake and secretion by the enterocyte during the past decade has challenged established assumptions, and the elucidation of the mechanisms of retinol intestinal absorption is in progress. After an overview of vitamin A and carotenoid fate during gastro-duodenal digestion, our focus will be directed to the putative or identified proteins participating in the intestinal membrane and cellular transport of vitamin A and carotenoids across the enterocyte (i.e., Scavenger Receptors or Cellular Retinol Binding Proteins, among others). Further progress in the identification of the proteins involved in intestinal transport of vitamin A and carotenoids across the enterocyte is of major importance for optimizing their bioavailability.

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Section: Overview Of Vitamin a And Carotenoid Fate During The Digementioning

confidence: 99%

Absorption of Vitamin A and Carotenoids by the Enterocyte: Focus on Transport Proteins

2013

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“…Generation and characterization of antibodies against peptides corresponding to the carboxyl-terminal ends of ES-4 (12 amino acids) and ES-10 (13 amino acids) will be described in detail elsewhere. 2 For Western blot analysis, proteins were separated by SDS-PAGE and electrotransferred onto nitrocellulose (Hybond-C, Amersham Corp). The membranes were blocked in 1% bovine serum albumin in Tris/NaCl/Tween 20 and incubated with primary antibodies.…”

Section: Materials-cholesterylmentioning

confidence: 99%

“…1 for a review). This enzyme is secreted by the pancreas into the intestinal lumen, where it can presumably hydrolyze dietary retinyl esters and other lipid esters (2)(3)(4)(5). The enzyme is also secreted by the liver (6), and its role in hepatic retinyl ester metabolism is under investigation but is presently unclear.…”

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confidence: 99%

“…Partial amino acid sequence analysis and immunoblot analysis show that the enzyme is highly related to or identical to rat liver carboxylesterase ES-2. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] C]oleate (1.96 GBq/mmol) and [1-14 C] palmitic acid (2.22 GBq/mmol) were purchased from Amersham; [carboxyl- 14 C]triolein (4.1 GBq/mmol) was from NEN Life Science Products; all-trans-retinol was from Sigma; octyl-␤-D-thioglucopyranoside (OSGP) 1 was from Calbiochem; DEAE-Sepharose CL-6B, Phenyl-Sepharose CL-4B, Sephadex G-100, and Sephacryl S-200 were from Pharmacia (Uppsala, Sweden). All chemicals used for sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were from Fisher Scientific; polyvinylidene difluoride membrane was from Bio-Rad.…”

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Purification and Characterization of a Neutral, Bile Salt-independent Retinyl Ester Hydrolase from Rat Liver Microsomes

Sun¹,

Alexson²,

Harrison³

1997

Journal of Biological Chemistry

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A neutral, bile salt-independent retinyl ester hydrolase (NREH) has been purified from a rat liver microsomal fraction. The purification procedure involved detergent extraction, DEAE-Sepharose ion exchange, PhenylSepharose hydrophobic interaction, Sephadex G-100 and Sephacryl S-200 gel filtration chromatographies, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The isolated enzyme has an apparent molecular mass of approximately 66 kDa under denaturing conditions on SDS-PAGE. Analysis of the amino acid sequences of four peptides isolated after proteolytic digestion revealed that the enzyme is highly homologous with other rat liver carboxylesterases. In particular, the sequences of the four peptides of the NREH (60 amino acids total) were identical to those of a rat carboxylesterase expressed in the liver ( Hydrolysis of retinyl esters occurs during both the hepatic uptake of newly absorbed dietary vitamin A and during the mobilization of retinyl ester stores from the liver. Thus, hepatic enzymes catalyzing the hydrolysis of retinyl esters are important in the body's overall vitamin A homeostasis. Earlier studies focused on a neutral, bile salt-dependent retinyl ester hydrolase that is now understood to be the enzyme carboxylester lipase (see Ref. 1 for a review). This enzyme is secreted by the pancreas into the intestinal lumen, where it can presumably hydrolyze dietary retinyl esters and other lipid esters (2-5). The enzyme is also secreted by the liver (6), and its role in hepatic retinyl ester metabolism is under investigation but is presently unclear. Carboxylester lipase has been cloned from several species, including the rat (see Ref. 7 for a review). In addition to carboxylester lipase, a number of tissues contain bile salt-independent retinyl ester hydrolase activities that have as yet not been fully purified or characterized biochemically (4, 8 -10). For example, we have previously demonstrated the occurrence of both acid and neutral retinyl ester hydrolase activities associated with rat liver microsomal preparations enriched in plasma membranes and endosomes (4, 10). We recently reported studies demonstrating the co-localization of newly delivered chylomicron retinyl esters and bile salt-independent retinyl ester hydrolase enzyme activities in the same plasma membrane/endosome fractions, and the in vitro hydrolysis of chylomicron remnant retinyl esters by these fractions (11). These studies suggested a probable role for these enzymes in the initial hepatic metabolism of chylomicron retinyl esters.In the present investigations, we have undertaken the purification and characterization of a neutral, bile salt-independent retinyl ester hydrolase from rat liver microsomes. The isolated enzyme has an apparent molecular mass of 66 kDa and catalyzes the hydrolysis of retinyl esters at higher rates than triglyceride hydrolysis. It shows no cholesteryl ester hydrolase activity. Partial amino acid sequence analysis and immunoblot analysis show that the enzyme is highly related to or ident...

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“…Cependant, des etudes sur cellules surexprimant cette prot eine ou sur souris knock-out ont montr e que la CEH n' etait pas significativement impliqu ee dans l'hydrolyse des esters de r etinol in vivo (van Bennekum et al, 1999 ;Weng et al, 1999). Par ailleurs, 3 etudes sur 4 ont montr e que la LP pouvait hydrolyser le r etinyl palmitate in vitro (Erlanson et Borgstrom 1968 ;Lindstrom et al, 1988 ;van Bennekum et al, 1999), hydrolyse pouvantêtre compl et ee par la lipase apparent ee de type II . En ce qui concerne les formes est erifi ees de vitamine E, il a et e sugg er e qu'elles pouvaientêtre hydrolys ees, soit par les enzymes du suc pancr eatique comme la CEH (Lauridsen et al, 2001 ;Moore et al, 1995), soit par des est erases ent erocytaires (Mathias et al, 1981).…”

Section: Digestionunclassified

Absorption intestinale des vitamines liposolubles

Reboul¹

2011

OCL

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The identity of vitamin A esterase activity of rat pancreatic juice

Cited by 44 publications

References 5 publications

Absorption of Vitamin A and Carotenoids by the Enterocyte: Focus on Transport Proteins

Absorption of Vitamin A and Carotenoids by the Enterocyte: Focus on Transport Proteins

Purification and Characterization of a Neutral, Bile Salt-independent Retinyl Ester Hydrolase from Rat Liver Microsomes

Absorption intestinale des vitamines liposolubles

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