Mobilizing lipase

Performing a systematic comparison of lipase-catalyzed kinetic resolutions of several seeondaiy aleohols in continuous flow mode (Figure 7) and shake flask batch mode using immobilized and non-mobilized lipases was reported by Csajagi and eo-workers [25]. The results indieated that immobilized as well as lyophilized powder forms of liphases can be effeetively used in eontinuous flow mode kinetie resolutions of raeemic alcohols in non-aqueous solvent systems. The produetivity of the lipases was higher in continuous flow reactors than in batch mode systems, whereas the enantiomer selectivities were similar. 

In a state of caloric excess, high insulin levels promote glucose uptake and prevent activation of mobilizing lipase. Glycerol 3-phosphate is therefore abundant, the rate of triacylglycerol synthesis is high, ex-... 

In short-term starvation, low insulin levels lead to a decreased glucose uptake, with a consequent decrease in the supply of glycerol 3-phosphate. Re-es-terification is retarded, and fatty adds are exported. Activation of mobilizing lipase is not significant in short-term starvation. 

Long-term starvation, exercise or stress leads to increased activity of mobilizing lipase. In stress and exercise, the catecholamines (adrenalin and noradrena-lin) are mainly responsible for the observed increase of mobilizing lipase activity, by their stimulation of adenylate kinase. Insulin reverses this activation by catecholamines. In long-term starvation, lack of insulin and excess growth hormone cause increased cAMP synthesis, leading to stimulation of mobilizing lipase. Re-esterification is also retarded (lack of insu-... 

Mobilizing lipase, or Hormone - sensitive triacylglycerot lipase EC3.U.3 [This reaction is relatively slow, and therefore rate-limiting]... 

Entrapment immobilization refers to the capture of enzymes within a polymeric network or microcapsules of polymers that allows the substrate and products to pass through but retains the enzyme. After entrapment, lipase proteins are not attached to the polymeric matrix or capsule, but their diffusion is constrained. Compared with physically adsorbed lipases, entrapment-mobilized lipases are more stable. Entrapment immobilization is relatively more simple to perform than covalent bonding, while the activity of lipases is maintained. However, when entrapped lipases are used for biodiesel production, the conversion rate is relatively low. In addition, the entrapped lipases also show relatively low stability (Zhang et al., 2012a). 

The neurohormonal control of lipid metabolism chiefly affects the mobilization and synthesis of triglycerides in the fat tissue. The lipolysis in tissues is dependent upon the activity of triglyceride lipase. All the regulators that favour the conversion of the inactive (nonphosphorylated) lipase to the active (phosphoiylated) one, stimulate the lipolysis and the release of fatty acids into the blood. Adrenalin... 

The major hormone-sensitive control point for the mobilization of fat and the (f-oxidation pathway is the effect of phosphorylation on the activity of the hormone-sensitive lipase of the adipose tissue. The major direct control point for (f oxidation is the inhibition of carnitine acyl-... 

Adipose Adipose tissue is the primary storage facility for fat. Fat is stored in these tissues as an intracellular droplet of insoluble triglyceride. A hormone-sensitive lipase mobilizes triglyceride stores by hydrolysis to free fatty acids. 

Indeed, the mobility of the entrapped dopant is crucial in promoting the reactivity of the final materials. Thus, provided that the dopant molecules are at the surface and enjoy enough freedom, high porosity will certainly promote reactivity by limiting intraparticle diffusion but that will not be the case if microporous xerogels of different HLB are compared (c/. entrapped lipase and tetra-//-propy 1 am monium perruthe-nate (TPAP) where ORMOSIL with the smaller pores are more reactive). 

In this context the lipase was immobilized on a support which also adsorbed water and propionic acid. During the reaction, the water caused a decrease of the reaction rate. While the water adsorption on the catalyst results in a reversible decrease of the enzyme activity, an excessive accumulation of water in the bulk mobile phase resulted in rapid irreversible deactivation of the enzyme. 

Figure 9.11 Lipid mobilization by hormone sensitive lipase (HSL)...

LANGMUIR TROUGH AND BALANCE LIPOPROTEIN LIPASE MICELLES LIPID ACTIVATION Lipid mobilization kinetics,... 

The final step in signal transduction is the action of cAMP on the regulatory subunit of the enzyme, protein kinase A. This ubiquitous enzyme then phosphorylates and activates enzymes with functions specific to different cells and organs. In fat cells, protein kinase A activates lipase, which mobilizes fatty acids in muscle and liver cells, it regulates glycogenolysis and glycogen synthesis. 

Hormone-sensitive lipase PMRRSV Triacylglycerol mobilization and fatty acid oxidation... 

Chylomicrons deliver tiiacylglycerols to tissues, where lipoprotein lipase releases free fatty acids for entry into cells. Triacylglycerols stored in adipose tissue are mobilized by a hormone-sensitive triacylglycerol lipase. The released fatty acids bind to serum albumin and are carried in the blood to the heart, skeletal muscle, and other tissues that use fatty acids for fuel. 

The mobilization of stored fat requires the hydrolytic release of fatty adds and glycerol from their TAG form. This process is initiated by hormone-sensitive lipase, which removes a fatty acid from carbon 1 and/or carbon 3 of the TAG. Additional lipases specific for diacylglyc-erol or monoacylglycerol remove the remaining fatty acids. 

Fatty acids are carried to tissues for use in synthesis of triacylglycerols, phospholipids, and other membrane lipids. The mobilization of fatty acids from triacylglycerol stores and from cholesterol esters depends upon hormone-sensitive lipase (p. 635).53b/ 53c This enzyme is activated by cAMP-dependent phos-... 

Jung, K. M., Astarita, G., Zhu, C., Wallace, M., Mackie, K., and Piomelli, D. (2007). A key role for diacylglycerol lipase-alpha in metabotropic glutamate receptor-dependent endocannabinoid mobilization. Mol Pharmacol 72, 612-621. 

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