Range of Substrates

Since the longer the carbon chain length of the solute, the lower is the water solubility and the more limited are the options for biological treatment. The efficiency of dehydrated cells in hydrolyzing a range of halogenated compounds was also examined [14]. 

The dehalogenase activity of dehydrated cells of R. erythropolis, for both chlorinated and brominated compounds, increases with the carbon chain length of the compound (up to 1-chlorohexane and 1-bromohexane). The opposite has been reported for the aqueous phase for both the isolated enzyme [54] and resting cells [14]. Eliminating solubilization requirements also clearly improves rates of 

Taken together, these results indicate that dehydrated cells could be an alternative catalyst for the conversion of poorly water-soluble compounds and that it might be possible to treat a mixture of pollutants by combining strains. Nevertheless, for future application the improvement of catalyst stability is still needed and is currently being studied. 

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The relative contributions from these processes strongly depend on the reaction conditions, such as type of solvent, substrate and water concentration, and acidity of catalyst (78,79). It was also discovered that in acid—base inert solvents, such as methylene chloride, the basic assistance requited for the condensation process is provided by another silanol group. This phenomena, called intra—inter catalysis, controls the linear-to-cyclic products ratio, which is constant at a wide range of substrate concentrations. 

Triphenylmethane dyes comprise one of the oldest classes of synthetic dyes. They are of bdUiant hue, exhibit high tinctorial strength, are relatively inexpensive, and may be appHed to a wide range of substrates. However, they are seriously deficient in fastness properties, especially fastness to light and... 

Hydrolytic enzymes such as esterases and Upases have proven particularly useful for asymmetric synthesis because of their abiUties to discriminate between enantiotopic ester and hydroxyl groups. A large number of esterases and Upases are commercially available in large quantities many are inexpensive and accept a broad range of substrates. 

The development of the all-polyethylene sack has somewhat reduced the relative importance of extrusion coating. At one time paper-polyethylene laminates were widely used for sacks but their use has declined. However, techniques have been developed for coating a wide range of substrates to provide a useful range of materials of interest to the packaging industry. 

C fi3 diamond films can be deposited on a wide range of substrates (metals, semi-conductors, insulators single crystals and polycrystalline solids, glassy and amorphous solids). Substrates can be abraded to facilitate nucleation of the diamond film. 

A wide range of substrates can be bonded. The inherent tackiness of natural rubber enables it to coat most non-polar substrates (mainly plastics and rubbers). 

Wide range of substrates. CR adhesives bond to almost any high-polar surface, as well as many low-polar surfaces (including polyolefins). 

Although the B-side is only stable for about a day, this composition gives surprisingly good performance on a range of substrates, as Table 2 illustrates [8j. 

These results demonstrate some interesting chemical principles of the use of acrylic adhesives. They stick to a broad range of substrates, with some notable exceptions. One of these is galvanized steel, a chemically active substrate which can interact with the adhesive and inhibit cure. Another is Noryl , a blend of polystyrene and polyphenylene oxide. It contains phenol groups that are known polymerization inhibitors. Highly non-polar substrates such as polyolefins and silicones are difficult to bond with any technology, but as we shall see, the initiator can play a big role in acrylic adhesion to polyolefins. 

Further progress in multiphasic catalysis will rely on the development of alternative techniques that allow the reactivity of a broader range of substrates, the efficient separation of the products, and recovery of the catalyst, while remaining economically viable. 

Different enzymes have different specificities. Some, such as amylase, are specific for a single substrate, but others operate on a range of substrates. Papain, for instance, a globular protein of 212 amino acids isolated from papaya fruit, catalyzes the hydrolysis of many kinds of peptide bonds. In fact, it s this ability to hydrolyze peptide bonds that makes papain useful as a meat tenderizer and a cleaner for contact lenses. 

Stockman has reported the preparation of alkyl-, aryl-, and vinyl-disubstituted aziridines with good diastereoselectivities and in good yields through treatment of tert-butylsulfmylimines with the ylide 119, derived from S-allyl tetrahydrothio-phenium bromide (Scheme 1.39) [64]. A range of substrates were tolerated, including heterocyclic, aromatic, and aliphatic substrates (Table 1.16). 

The development of Sharpless asymmetric epoxidation (SAE) of allylic alcohols in 1980 constitutes a breakthrough in asymmetric synthesis, and to date this method remains the most widely applied asymmetric epoxidation technique [34, 44]. A wide range of substrates can be used in the reaction ( ) -allylic alcohols generally give high enantioselectivity, whereas the reaction is more substrate-dependent with (Z)-allylic alcohols [34]. 

The answer is, generally, no. Most of the enzymes involved are specific in terms of the reaction they catalyse, but will work with a range of substrates. Some Candida sp for example contain an enzyme system which will convert n-alkanes into alkane dioic adds ... 

The rate parameters for the reactions of e (aq) with substrates are generally determined by monitoring the disappearance of the hydrated electron at 600-700 nm. The first order rate parameters are generally determined over a range of substrate concentrations and the second order rate parameter calculated from the resulting linear relation. The data available for such studies with Pu ions are presented in Table IV. 

Finally, if the phosphorylation of myosin is the activation mechanism, then dephosphorylation is likely to be the deactivation mechanism, and so it seems. However, there are several myosin phosphatases in smooth muscle cells and they have some range of substrate specificities. Thus, there are several possible candidates for a regulatory role. 

FIGURE 2.8 Monooxygenase activities of mammals, birds, and fish, (a) Mammals and birds, (b) Mammals, birds, and fish. Activities are of hepatic microsomal monooxygenases to a range of substrates expressed in relation to body weight. Each point represents one species (males and females are sometimes entered separately) (from Walker et al. 2000). 

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