| 1. |
- Andersson, Lena, et al.
(författare)
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Pancreatic lipase related protein 2, but not classical lipase hydrolyzes galactolipids
- 1996
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Ingår i: Biochimica et Biophysica Acta. - : Elsevier BV. - 0006-3002. ; 1302:3, s. 236-240
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Tidskriftsartikel (refereegranskat)abstract
- The pancreatic lipase family contains three subfamilies, the 'classical' lipases and the pancreatic lipase-related proteins 1 (PLRP1) and 2 (PLRP2). Galactolipids are present in membranes of leaves and vegetables and consist of digalactosyldiacylglycerol (DGalDG) monogalactosyldiacylglycerol (MGalDG) and sulfoquinovosyldiacylglycerol (SQDG). These lipids were incubated with PLRP2 from guinea-pig (GPLRP2) and rat (RPLRP2). In the presence of bile salts DGalDG was efficiently hydrolyzed by GPLRP2 and, although less efficiently, by RPLRP2 to digalactosylmonoacylglycerol (DGalMG), free fatty acids and water-soluble galactose-containing compounds. Also, MGalDG and SQDG were hydrolyzed by GPLRP2 and RPLRP2. These data suggest a possible role of PLRP2 in the digestion of dietary galactolipids
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| 2. |
- Gitlesen, Thomas, et al.
(författare)
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Adsorption of lipase on polypropylene powder
- 1997
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Ingår i: Biochimica et Biophysica Acta - Lipids and Lipid Metabolism. - 0005-2760. ; 1345:2, s. 188-196
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Tidskriftsartikel (refereegranskat)abstract
- Adsorption of different lipases by EP-100 polypropylene powder from pure and pure lipase preparations was studied. Langmuir isotherms described the adsorption equilibria well both for protein and lipase activity adsorption. Adsorption isotherms for five different proteins all gave a similar saturation level of 220 mg protein per g carrier. Twelve commercial lipase preparations were tested for selectivity in the adsorption of-lipase. For all preparations the selectivity factor was larger than one. In a crude lipase preparation from Pseudomonns fluorescence, the specific activity in solution decreased by two orders of magnitude after adsorption. The adsorption was not significantly influenced by pH changes in the adsorption buffer, indicating that hydrophobic and not electrostatic interactions are the dominating adsorption forces. Adsorption of a crude lipase from Candida rugosa (Sigma) was fast and equilibrium was reached in 30 and 100 min for protein and lipase activity adsorption respectively. Desorption in aqueous solution wag negligible. Investigations with seven different lipases showed no correlation between the specific lipolytic activity of dissolved enzyme in aqueous solution and the specific activity of adsorbed enzyme in an esterification reaction in organic solvent.
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| 3. |
- Ncube, Ignatious, et al.
(författare)
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Fatty acid selectivity of a lipase purified from Vernonia galamensis seed
- 1995
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Ingår i: Biochimica et Biophysica Acta - Lipids and Lipid Metabolism. - 0005-2760. ; 1257:2, s. 149-156
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Tidskriftsartikel (refereegranskat)abstract
- Vernonia galamensis is an annual herb whose seed oil contains high levels of an epoxy fatty acid, vernolic (cis-12,13-epoxy cis-9-octadecenoic) acid. The seed also contains lipase activity in the dormant state. A lipase was purified from the seed and its substrate specificity studied in isooctane. The lipase shows pronounced selectivity for the native triacylglycerol, trivernolin. The rate of hydrolysis of triolein, the corresponding non epoxy triacylglycerol, is only 3% of that of trivernolin. In the acidolysis of tricaprylin using a mixture of fatty acids, the Vernonia lipase also showed selectivity for vernolic acid. Michaelis-Menten kinetics of the hydrolysis of triacylglycerols revealed that the observed high selectivity of the Vernonia lipase for trivernolin was mainly due to a higher Vmax for trivernolin. The Vmax value for the hydrolysis of trivernolin was 5 times higher than that for triolein. This novel substrate specificity is an adaptation by the seed lipase to the triacylglycerols of the seed oil that contain up to 80% vernolic acid.
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| 4. |
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| 6. |
- MARTINELLE, M, et al.
(författare)
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ON THE INTERFACIAL ACTIVATION OF CANDIDA-ANTARCTICA LIPASE-A AND LIPASE-B AS COMPARED WITH HUMICOLA-LANUGINOSA LIPASE
- 1995
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Ingår i: BIOCHIMICA ET BIOPHYSICA ACTA-LIPIDS AND LIPID METABOLISM. - ROYAL INST TECHNOL,DEPT BIOCHEM & BIOTECHNOL,S-10044 STOCKHOLM,SWEDEN. : ELSEVIER SCIENCE BV. - 0005-2760. ; 1258:3, s. 272-276
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Tidskriftsartikel (refereegranskat)abstract
- The interfacial activation of Candida antarctica lipase A (CALA) and B (CALB) has been investigated and compared with that of Humicola lanuginosa lipase (HLL). CALB displayed no interfacial activation towards p-nitrophenyl butyrate (PNPB) when exceeding the solubility limit of the substrate. No activation was observed towards p-nitrophenyl acetate (PNPA) at the addition of sodium dodecyl sulfate (SDS) nor in the presence of a solid polystyrene surface. The catalytic action of CALB was very different from that of Humicola lanuginosa lipase, which showed a pronounced interfacial activation with the same substrates. The basis for the anomalous behaviour of CALB is proposed to be due to the absence of a lid that regulates the access to the active site. in contrast to CALB, CALA expressed interfacial activation, but the activation was not as prominent as for Humicola lanuginosa lipase (HLL). The structural basis for the activation of CALA is unknown.
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