References

Naemura, K. (1994) Stereoselectivity of enzymatic hydrolyses and acylations. J. Synth. Org. Chem. Jpn. 52, 49-58. (in Japanese) 2. Kazlauskas, R. J., Weissfloch, A. N. E., Rappaport, A. T., and Cuccia, L. A. (1991) A rule to predict which enantiomer of a secondary alcohol reacts faster in reactions catalyzed by cholesterol esterase, lipase from Pseudomonas cepacia, and lipase from Candida rugosa. J. Org. Chem. 56, 2656-2665. 3. Burgess, K. and Jennings, L. D. (1991) Enantioselective...

Simple Procedure for the Screening of Enzyme Reactions

The following enzymes (100mg of each) (1) Lipase AP6 (Aspergillus niger, Amano), (2) lipase AY-30 (Candida cylindracea, Amano), (3) Candida cylindracea lipase (Meito-Sangyo), (4) lipase GC4 (Geotrichum candidum, Amano), (5) lipase MAP (Mucor meihei, Amano), (6) lipase MAP (Mucor meihei, Amano), (7) lipase N (Rhizopus niveus, Amano), (8) Lipase OF (Candida cylindracea, Meito-Sangyo), (9) Lipase R (Humicola sp., Amano), (10) Lipase R-10 (Humicola lanuginosa, Amano), (11) Candida rugosa lipase...

Nocardia rhodocrous Cells

Thawed cells of N. rhodocrous (1 g wet cells), suspended in 2.0 mL of a water-saturated mixture of benzene and n-heptane (1 1, v v) under mild soni- Fig. 3. Schematic model of lipid-coated lipase entrapped in hydrophobic photo-crosslinked resin gel matrix. Fig. 3. Schematic model of lipid-coated lipase entrapped in hydrophobic photo-crosslinked resin gel matrix. cation (10 kHz for several seconds), were mixed with 1.0 mL of the same solvent containing 1.0 g of ENTP or ENTB and 10 mg of benzoin...

Notes

Trimethylsilylmethanol is a better substrate not only for lipase OF 360 but also for other lipases from different sources such as lipase Saiken 100 (Rhizopus japonicus, Osaka Saikin Kenkyusho Co., Osaka, Japan) and lipase (Steapsin) (hog pancreas, Tokyo Kasei Kogyo, Tokyo, Japan). 2. Trimethylsilylmethanol is also a very useful substrate for the enantioselective esterification of racemic naproxen 2-(6-methoxy-2-naphthyl)propionic acid , a nonsteroidal anti-inflammatory drug, by C. cylindracea...

Hydrolytic Enzymes

Modification of Lipase from Pseudomonas with Activated PEG2 (3) To 100 ml of 0.2 M sodium borate buffer (pH 9.5) containing 1 g of lipase from P. fragi is added stepwise 9.1 g of activated PEG2 under stirring (1.5-2.0 g h). The reaction mixture is stirred at 25 C for 5 h (see Note 3). Then, the reaction is stopped by adding 10 times the volume of 0.1 M borate buffer (pH 8.0) and then the sample solution is concentrated to one-tenth by an Amicon Diaflo YM100 ultrafiltration membrane...

A

Fig. 28. (A) Empirical rule which predicts the faster reacting enantiomer of secondary alcohols with hydrolases, e.g., C. rugosa (adapted from ref. 57). (B) The faster-reacting (2S,3R)-29 obeys the model. Fig. 28. (A) Empirical rule which predicts the faster reacting enantiomer of secondary alcohols with hydrolases, e.g., C. rugosa (adapted from ref. 57). (B) The faster-reacting (2S,3R)-29 obeys the model. shown by this group of enzymes agrees with the model proposed by Kazlauskas (57,58),...

Adsorption of Sugars onto a Solid Support

Prepare methanolic solution (20 mL) containing 1 g of glucose or fructose. 2. Add 0.5 g of silica gel or a-cellulose, under stirring at room temperature. Stir the mixture for 30 min. (See Note 1.) 3. Evaporate the methanol under continuous agitation at reduced pressure and dry resulting homogenous powder over P2O5 for 72 h. Fig. 1. Schematic representation of the enzymatic esterification of glucose preadsorbed on silica gel in supercritical CO2. Fig. 1. Schematic representation of the enzymatic...

Benzyloxy3Pentanol 29 as a Precursor to

The required (2S,3S)-formylhydrazine (6) was initially prepared from ethyl lactate, which provided the C2 chiral center (Fig. 24). Subsequent chain elongation Fig. 24. Preparation of (2S,3S)-formylhydrazine fom ethyl lactate. Fig. 24. Preparation of (2S,3S)-formylhydrazine fom ethyl lactate. via the pyrrolidine amide 27 provided ketone 28. However, under all conditions tried, reduction of 28 resulted in a mixture (90 10) of the (2S,3R)- and (2S,3S)- 2-benzyloxy-3-pentanol (29), with separation...

Celite as a Support for Biocatalysts

Celite is a solid support widely used for the adsorption of biocatalysts. Many examples of improved enzyme performances by means of adsorption onto From Methods in Biotechnology, Vol. 15 Enzymes in Nonaqueous Solvents Methods and Protocols Edited by E. N. Vulfson, P. J. Halling, and H. L. Holland Humana Press Inc., Totowa, NJ Celite powder are reported in the literature (5-16). Porous Celite beads and rods are used primarily as supports for the immobilization of whole cells (17-19) and fungi...

Enzymatic Desymmetrization of Diol

In the improved synthesis (20), shown in Fig. 6, a diol olefin 13 could be quickly assembled from bromodifluorobenzene. This underwent an iodocyclization reaction to form a 2,2,4-trisubstituted tetrahydrofuran in which the desired ds-isomer 14 predominated (85 15 cis-.trans) (21,22). Introduction of the triazole followed by formation of the chlorosulfonate provided the key intermediate 5, which could be condensed with the side chain to form SCH56592. Like the (KJ-triol 8 in the previous route,...

Entrapment of Biocatalysts by Prepolymer Methods

Entrapment of biocatalysts should be carried out under mild conditions, especially when synthetic polymer materials are used as supports. In the case of photo-crosslinkable resin prepolymers having photosensitive functional groups, irradiation of near-ultraviolet (UV) light (maximum intensity at 365 nm) induces radical polymerization of the prepolymers and gel formation completes within a few minutes. Various types of prepolymers with different chain lengths, ionic properties, and or...

Synthesis of Imidoesters

Synthesis of imidoesters are according to the procedure adapted from Hunter and Ludwig 4 as described by CH3OH, 0 C, 1.5 h OCH nitrile OCH3 Imidoesters with different hydrophobicity could be synthesized easily from their corresponding nitriles or alcohols in relatively high yield. Methyl acetimidate imidoester I methyl benzimidate imidoester II , methyl 3-phenylpropionimidate imidoester V , and methyl 4-phenylbutyrimidate imidoester VI are very soluble in aqueous 0.1 M borate buffer, pH 8.5....

Adrie J J Straathof Mike J J Litjens and Joseph J Heijnen 1 Introduction

Biotransformations in organic media with none of the components being in suspension are rare. As enzymes are virtually insoluble in organic solvents, homogeneous reactions are only feasible if the enzyme is solubilized by, for example, chemical modification 1 or coating it with a lipid 2 . In general, one or more components are present in the reaction mixture in solid state i.e., the enzyme, substrate s , product s , and adsorbents e.g., molecular sieves or a mixture of a salt and its hydrate ....

Methods 21 Pervaporation

Pervaporation is defined as a separation technique in which a liquid feed mixture is separated by partial vaporization through a nonporous permselective selectively permeable membrane 11 . Transport phenomena in pervaporation are different when compared to any other membrane processes such as dialysis, reverse osmosis, and ultrafiltration because of multiple interactions From Methods in Biotechnology, Vol. 15 Enzymes in Nonaqueous Solvents Methods and Protocols Edited by E. N. Vulfson, P. J....

Enzymatic Approaches to the Chiral Tetrahydrofuran Sulfonate 5 21 Enzymatic Desymmetrization of RTriol

The initial synthesis of the key 2,2,4-trisubstituted tetrahydrofuran 5 was somewhat lengthy Fig. 3 12 . The -tertiary hydroxyl chiral center was introduced Fig. 2. Two chiral key intermediates Fig. 2. Two chiral key intermediates 9 R Ts 10a Cis 40 60 10b Trans Fig. 3. Differentiating between primary alcohols. 9 R Ts 10a Cis 40 60 10b Trans Fig. 3. Differentiating between primary alcohols. via a Sharpless-Katsuki epoxidation of the allylic alcohol 7, followed by introduction of the triazole and...

Shinobu Oda Takeshi Sugai and Hiromichi Ohta 1 Introduction

Using this device referred to interface bioreactor, various microbial transformations of lipophilic substrate with a growing and or living microorganism can be efficiently performed in a hydrophobic organic solvent see Fig. 1 and reviews in refs. 1 and 2 . In the device, the microorganism can grow using nutrients and water in the hydrophilic carrier and oxygen in the organic phase and spontaneously forms a thick microbial film on the surface of the carrier. Various lipophilic organic compounds...

Imprinting Enzymes for Use in Organic Media

Dordick 1. Introduction Enzymes suspended in nonaqueous media are more rigid than in aqueous media 1,2 . This increased rigidity is thought to be the result of increased electrostatic and hydrogen-bonding interactions among the surface residues of the protein in organic solvents 3 . Despite this rigidity, enzymes remain active and selective in organic solvents, and this has led to a large number of applications that have impacted the chemical, pharmaceutical, and...

Humana Press fe Totowa New Jersey

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Enhancement of Enzyme Activity Using Salt Hydrate Pairs

It is well known that a salt hydrate pair can control the water level in the reaction mixture by taking up or releasing water as required to keep a constant aw condition during the reaction. Each kind of salt hydrate pair has a typical aw 5 . When a hydrated salt and its corresponding lower hydrate or anhydrous form are present together, ideal behavior implies a fixed equilibrium water vapor pressure and, hence, constant aw, whatever the relative quantities of the two forms. Although the salts...

Organosilicon Compounds as Novel Substrates

Comparative studies were made by the use of organosilicon compounds having a different chain length between hydroxyl group and the silicon atom Me3Si CH2 nOH, n 0, 1, 2, and 3 and the corresponding carbon compounds Me3C CH2 nOH, n 0, 1, and 2 as another substrate acyl acceptor in the enantioselective esterification of 2- 4-chlorophenoxy propanoic acid, whose -enantiomer is useful as a herbicide, with lipase OF 360 of Candida cylindracea Fig. 1 in benzene. The effects of the silicon atom on the...

Hydration Properties of Celite R640 in Vapor Phase

A general method for performing biotransformations at known water activity consists of exposing each component of the reaction mixture to a vapor phase characterized by a constant known relative humidity 33,34 . In principle, the phases, once mixed, reach the equilibrium water activity. Figures 5 and 6 show the rate of equilibration of dry Celite R-640 batch 3, Fig. 1 exposed to atmospheres generated by saturated salt solutions or pure water Fig. 3. Adsorption isotherms equilibration time 24 h...

Some Basic Definitions and Calculations

The total water content of the system is often known from the recipe used to prepare it. However, it is usually not a particularly useful guide to behavior, From Methods in Biotechnology, Vol. 15 Enzymes in Nonaqueous Solvents Methods and Protocols Edited by E. N. Vulfson, P. J. Halling, and H. L. Holland Humana Press Inc., Totowa, NJ because the water will be partitioned between several different phases e.g., bound to the biocatalyst or support, dissolved in the organic phase, present in the...