Lipases factors affecting

Lipases are able to catalyze many hydrolytic and esterification reactions in the presence of different substrates. The type of substrate is a key factor affecting the activity and productivity of lipase-catalyzed reactions. 

Most, if not all, milks contain sufficient amounts of lipase to cause rancidity. However, in practice, lipolysis does not occur in milk because the substrate (triglycerides) and enzymes are well partitioned and a multiplicity of factors affect enzyme activity. Unlike most enzymatic reactions, lipolysis takes place at an oil-water interface. This rather unique situation gives rise to variables not ordinarily encountered in enzyme reactions. Factors such as the amount of surface area available, the permeability of the emulsion, the type of glyceride employed, the physical state of the substrate (complete solid, complete liquid, or liquid-solid), and the degree of agitation of the reaction medium must be taken into account for the results to be meaningful. Other variables common to all enzymatic reactions—such as pH, temperature, the presence of inhibitors and activators, the concentration of the enzyme and substrate, light, and the duration of the incubation period—will affect the activity and the subsequent interpretation of the results. 

Harper, W. J. and Gould, I. A. 1959. Some factors affecting the heat-inactivation of the milk lipase enzyme system. 15th Int. Dairy Congr. Proc. 6, 455-462. 

Nashif, S. A. and Nelson, F. E. 1953B. The lipase of Pseudomonas fragi. II. Factors affecting lipase production. J. Dairy Sci. 36, 471-480. 

Anderson, M. 1982a. Factors affecting the distribution of lipoprotein lipase activity between serum and casein micelles in bovine milk. J. Dairy Res. 49, 51-59. 

Bell, L.I., Parsons, J.G. 1977. Factors affecting lipase flavor in butter. J. Dairy Sci. 60, 117-122. 

H. H., Scheper, T Kolisis, F.N. (1993), Factors affecting the lipase catalyzed transesterification reactions of 3-hydroxy esters in organic solvents, Tetrahedron Asymmetry 4, 1007 -1016. 

Yamane, T., Ichiryu, T., Nagata, M., Ueno, A., and Shimizu, S., Intramolecular esterification by lipase powder in microequeous benzene factors affecting activity of pure enzyme, Biotechnol. Bioeng., 36, 1063-1069, 1990. 

Various factors affect the enantioselectivity in such hydrolyses. These include the concentration and the choice of the organic solvent used.30 In another, pretreatment of the lipase with 2-propanol raised the enantioselectivity 25-fold to 93% ee.31 In an esterification of menthoi, coating the... 

Espinosa, E., S. Sanchez, and A. Farres. 1990. Nutritional Factors Affecting Lipase Production by Rhizopusdelemar CDBB H313. Biotechnology Letters 12 (3) 209-214. 

Reacting lipophilic substrates with hydrophilic compounds, as in the case of most transesteriflcation reactions, is one of the major difficulties in lipase-catalyzed reactions. Several parameters need to be considered to overcome this immiscibility problem. One commonly proposed strategy is the use of a nonaqueous medium. In this chapter, the advantages of using nonaqueous media in biochemical synthesis reactions, over aqueous and solvent-free systems, are discussed. The use of hydrophobic solvents is also discussed, followed by a presentation of the alternatives that can overcome the limitations of solvents. The focus of this chapter is mainly on the use of supercritical fluids (SCFs) as a green alternative reaction medium. The chapter also discusses ionic liquids (ILs) as another alternative. These solvents and the factors affecting their physical properties and their effect on the activity and stability of lipase are also discussed. 

FACTORS AFFECTING LIPASE ACTIVITY IN THE OIL PALM (ELAEIS GOmEESSlS) MESOCARP... 

The mesocarp of the ripe oil palm fruit accumulates large amounts of palm oil, an economically desirable product. The level of free fatty acids (FFA) is an important determincuit of oil quality and little is known of the factors affecting this parameter in the oil palm fruit. Evidence is presented here for the presence of an active endogenous lipase in the oil palm mesocarp. Lipase activity was located in the oil body fraction. Maximum in vitro activity was observed at 18°C but using an in vivo assay maximum activity was obtained at 5 C. Low temperature activation was less pronounced in a water-saturated environment. ... 

Sawae H, Sakaguchi A, Nakashio F, Goto M. 2005. Important factors affecting functions of PEG microspheres containing lipase complexes. / Chem Eng Japan 38 54-59. 

Enzymatic alcoholysis of PLs can be used to produce LPLs and fatty acid esters simultaneously. The main factors affecting enzymatic alcoholysis of PLs are the type of lipase and chain length of the alcohol. For example, immobilized RML exhibited significant preference for short chain alcohols like ethanol, whereas lipase TLL preferred long chain alcohol (Samey et al., 1994). Samey and co-workers (1994) reported that addition of a small amount of water to the reaction mixture increased the LPLs yield significantly. 

Figure 3 Factors affecting digestion, absorption, metabolism, and transport of carotenoids, crt, carotenoids CEH, carboxylic ester hydrolase, secreted by the pancreas LPL, lipoprotein lipase VLDL, very low-density lipoprotein LDL, low-density lipoprotein HDL, high-density lipoprotein.

Crucial factors affecting productivity of enzymatic biodiesel synthesis are shown in Fig. 7.5 (Szczesna-Antczak et al., 2009). To achieve the economic viabdity, the suitable raw materials and lipase have to be chosen. The latter can be modihed to improve stability and catalytic efficiency. These steps are followed by selection of organic solvent, optimization of substrate molar ratio, temperature, water activity, pH of enzyme s microenvironment, and the highest-permissible glycerol concentration in reaction products (the so-named subparameters). 

Lipases have also been used as initiators for the polymerization of lactones such as /3-bu tyro lac tone, <5-valerolactone, e-caprolactone, and macrolides.341,352-357 In this case, the key step is the reaction of lactone with die serine residue at the catalytically active site to form an acyl-enzyme hydroxy-terminated activated intermediate. This intermediate then reacts with the terminal hydroxyl group of a n-mer chain to produce an (n + i)-mer.325,355,358,359 Enzymatic lactone polymerization follows a conventional Michaelis-Menten enzymatic kinetics353 and presents a controlled character, without termination and chain transfer,355 although more or less controlled factors, such as water content of the enzyme, may affect polymerization rate and the nature of endgroups.360... 

Yang and Russell [7] made comparison of lipase-catalyzed hydrolysis in three different systems organic, biphasic, and reversed micelles. They affirmed that water content is an important factor that distinctly affects every system. Their results demonstrated that activity of lipase in organic-aqueous biphasic media was lower than that obtained in reversed micelles. However, better productivities were obtained in biphasic media, which were the most suitable environment. 

The location of the acyl chain is of primary importance in the binding process because of its size. Due to the movement of lid during interfacial activation, a hydrophobic trench is created between the lid and enzyme surface. The trench size is ideal to accommodate the acyl chain. Interactions between the non-polar residues of the trench and the non-polar acyl chain stabilize the coupling. It has been postulated that the configuration of the trench is responsible for substrate specificity. This hypothesis seems plausible since lipases usually discriminate against certain acyl chain lengths, degrees of unsaturation, and location of double bonds in the chain. Any of these factors could affect the interaction between the acyl chain and the trench. 

Supplementation of the substrate with oil led to an increase in lipase activity and a reduction in the time required to reach the maximum activity. This might be owing to acceleration of the metabolism of the microorganism. However, the time to reach the maximum must be analyzed carefully, since factors such as inoculum age and physiologic state may directly affect this result. 

Lipolysis in milk is affected by inhibiting and activating factors. As discussed above, proteose peptone fraction of milk can inhibit milk LPL while apolipoproteins stimulate the enzyme. This is particularly important in spontaneous lipolysis however, proteose peptone 3 has been shown to inhibit lipolysis induced by homogenization, sonication, and temperature activation (Arora and Joshi, 1994), while protein components of the milk fat globule membrane inhibit lipolysis caused by bacterial lipase (Danthine et al., 2000). Several exogenous chemical agents can also inhibit lipolysis (Collomb and Spahni, 1995). For example, polysaccharides such as X-carrageenan at 0.3 g/1 effectively inhibits lipolysis in milk activated by mechanical means or temperature manipulation (Shipe et al., 1982) and lipolysis caused by the lipase from P. fluorescens (Stern et al., 1988). 

Other factors. A cow s hormonal balance can affect the susceptibility of her milk to spontaneous lipolysis (Fredeen et al., 1951 Kastli et al., 1967 Bachman et al., 1988). The oestrus cycle appears to have little effect on spontaneous lipolysis (Fredeen et al, 1951) but may affect lipase activity in the milk (Kelly, 1945). In contrast, treatment of cows with oestradiol and progesterone has been shown to lead to increased lipolysis in the milk (Bachman, 1982 Heo, 1983 Bachmann eta/., 1985) but no change (Bachman, 1982) or a transient increase (Bachmann et al., 1985) in total lipase activity. It appears that the increased lipolysis in milk following hormonal treatment, or in milk from cows with ovarian cysts, may not be typical spontaneous lipolysis as cooling is not needed to initiate it (Bachman, 1982) a lipase other than lipoprotein lipase, possibly a bile salt-stimulated lipase, may be responsible for such lipolysis (Heo, 1983 Bachmann et al., 1985). Treatment of cows with bovine somatotropin has been reported to have no significant effect on milk lipoprotein lipase activity (Azzara et al., 1987). 

Nielsen, J.V. 1978. Technical factors in cooling which are thought to affect lipase activity in milk. Nord. Mejeriind. 5, 9-12, 20. 

This article reviews the main applications of glycosidases and lipases in the synthesis of glycosidic bonds and in acylation/deacylation reactions of carbohydrates, respectively. Special attention is given to the factors that can affect the selectivity of the reactions, such as the enzyme origin, the structure of the substrates, and the reaction medium. A number of reviews have appeared in the literature on enzymatic synthesis of carbohydrates that include reactions with glycosidases and/or lipases [ 1 - 6]. In this article only a selection of examples are given to illustrate the discussion, rather than an extensive compilation of the work published in the area. 

Factors that Affect Lipase-Catalyzed Reactions... 

The sensitivity and specificity of these tests are limited by the complexity of the processes of absorption and metabolism. The substrates are specific for pancreatic lipases and the product is absorbed independently of micelle formation, but the results of the test are affected by other factors, such as gastric emptying, mucosal absorption, hepatic metabolism, endogenous "CO2, and total CO2 production. These factors may explain the test s limited diagnostic sensitivity in mild and moderate pancreatic insufficiency and its lack of specificity in nonpancreatic GI diseases. 

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