Search results for " lipase"

Study of a lipase from Candida rugosa Diddens and Lodder

1993

Lipasic system of Candida rugosa (CBS 613) strain was studied. The enzyme was purified in one step by hydrophobic chromatography. The properties of this lipase were determined. It is an oligomeric enzyme composed of five identical monomers of 46 kg · mol−1. Its optimum reaction conditions are pH = 7 and temperature = 40°C. This enzyme presents a rapid thermal denaturation and then a more stable form. It is a cell-bound lipase which is induced by triacyl glycerols. This enzyme presents a high specificity for external positions on glycerol. Unterschung einer Lipase aus Candida rugosa Diddens und Lodder Die Reinigung einer Lipase aus Candida rugosa (CBS 613) wurde in einer einzigen Stufe durch…

Lipase-enhanced activity in flavour ester reactions by trapping enzyme conformers in the presence of interfaces

1998

In order to improve the lipase-catalyzed synthesis of flavour esters, we have used the reported strategy of interfacial activation-based molecular (bio)imprinting [Mingarro et al. 1995. Proc. Natl. Acad. Sci. U.S.A. 92: 3308], later called trapping in the presence of amphiphile interfaces (TPI) [Mingarro et al. 1996. Biochemistry 35: 9935]. Five lipases of fungal and mammalian origin typically used for esterification process have been explored to improve production by TPI treatment. A marked enhancement of enzymatic activity has been observed in all TPI-treated lipases assayed and the activation factor obtained was up to 90-fold. The dependence on chain length of acyl donors in the esterifi…

Effects of combined estrogen+progestin hormone therapy on hepatic lipase and lipoprotein lipase levels

2005

Biocatalyzed acidolysis of soybean oil triacylglycerols to increase oleic acid content

2004

Lipase catalyzed acidolysis of triacylglycerols (TAG) of soybean oil with oleic acid in organic solvent was studied; immobilized lipase from Rhizomucor miehei was used and the effects of reaction time, incubation temperature and enzyme load on TAG total and positional fatty acid (FA) percentage compositions were investigated. The results show that oleic acid incorporation was high after 24 and 48 h, while after 72 h a lower level of oleic acid in TAG was observed. Moreover, for the reactions carried out at 30 and 40 degrees C, it was observed that the oleic acid level was about 46.5% while ligtly higher values (about 49%) were observed at 50 degrees C; however, under this last condition, th…

Age-related changes in the endocannabinoid system in the mouse hippocampus.

2015

Previous studies have demonstrated that the endocannabinoid system significantly influences the progression of brain ageing, and the hippocampus is one of the brain regions most vulnerable to ageing and neurodegeneration. We have further examined age-related changes in the hippocampal endocannabinoid system by measuring the levels of anandamide (AEA) and 2-arachidonoylglycerol (2-AG) in young and old mice from two different mouse strains. We found a decrease in 2-AG but not AEA levels in aged mice. In order to identify the cause for 2-AG level changes, we investigated the levels of several enzymes that contribute to synthesis and degradation of 2-AG in the hippocampus. We found a selective …

Different effects of pioglitazone and rosiglitazone on lipid metabolism in mouse cultured liver explants.

2010

Background Pioglitazone (PIO) and rosiglitazone (ROSI) are widely used as oral antidiabetic agents for treatment of type 2 diabetes. Although these medications exert similar effects on blood glucose, recent clinical studies indicated that PIO has a more pronounced beneficial effect on lipid parameters than ROSI. In order to get further insight into the lipid effects of both drugs, we tested whether PIO, compared to ROSI, could exert direct effects on lipid liver metabolism in relation with plasma lipids. Methods We performed in vitro studies using mice liver slices incubated 21 h either with ROSI (1 µmol/L) or PIO (7.5 µmol/L). Results We showed that both glitazones slightly reduced HMG-CoA…

Effects on lipoprotein subclasses of combined expression of human hepatic lipase and human apoB in transgenic rabbits

2003

Objective— The effects of combined expression of human hepatic lipase (HL) and human apolipoprotein B (apoB) on low-density lipoprotein (LDL) subclasses were examined in rabbits, a species naturally deficient in HL activity. Methods and Results— In apoB-transgenic rabbit plasma, >80% of the protein was found in the 1.006- to 1.050-g/mL fraction. Gradient gel electrophoresis (GGE) of this fraction revealed two distinct species, designated large and small LDL. A denser fraction (d=1.050 to 1.063 g/mL) contained small LDL as well as another discrete LDL subspecies, designated very small LDL. Expression of HL resulted in reductions in protein concentrations in the 1.006- to 1.050-g/mL densi…

The lipoprotein lipase activity in cultured beating heart cells of the post-natal rat.

1974

Summary The lipoprotein lipase (LPL) activity was studied in cultured beating heart cells of the post natal rat as a function of the culture age, from the freshly trypsinized cell suspension up to the 14th day of culture. The LPL activity remains at a practically stationary level during the first four days of culture, and then increases rapidly to reach a plateau, at a level 3–4 times higher at the 21th day of culturing. The significance of this enzymatic activity progression comparing to 3H thymidine incorporation from the point of view of cell differentiation is discussed. Our results suggest that after the 12th day of culture, cells contain their optimal enzymatic apparatus for lipid met…

Dietary cholic acid lowers plasma levels of mouse and human apolipoprotein A-I primarily via a transcriptional mechanism

2000

To induce dietary atherosclerosis in mice, high-fat/high-cholesterol (HF) diets are frequently supplemented with cholic acid (CA). This diet produces low plasma levels of high-density lipoprotein (HDL) and high levels of low-density lipoprotein (LDL). However, HF diets without any added CA, which more closely resemble human diets, increase levels of both HDL and LDL, suggesting that CA may be responsible for the lowering of HDL. Our aim was to examine the potential mechanism responsible for the lowering of HDL. Nontransgenic (NTg) C57BL mice and apoA-I-transgenic (apoAI-Tg) mice, with greatly increased basal apoA-I and HDL levels, were used. Mice were fed the following four diets: control (…

Transient chylomicronemia preceding the onset of insulin-dependent diabetes in a young girl with no humoral markers of islet autoimmunity

2004

OBJECTIVE: We investigated the possible causes of diabetes in a young child who presented with hyperglycemia associated with severe hypertriglyceridemia (>166 mmol/l), hypercholesterolemia (>38 mmol/l) and fasting chilomicrons. RESULTS: The patient did not have any of the HLA and autoantibody markers typically associated with type 1 diabetes. A glucose clamp failed to demonstrate insulin resistance (peripheral glucose utilization rate (M)=4.3 mg/kg per min) and there was no family history of type 2 diabetes or maturity onset diabetes in youth. Both fasting and stimulated C-peptide levels, including those in response to i.v. glucagon, were below the limit of detection. This is consiste…