Enzymes types

Enzymes not only produce characteristic and desirable flavor (79) but also cause flavor deterioration (80,81) (see Enzyme Applications, Industrial). The latter enzyme types must be inactivated in order to stabilize and preserve a food. Freezing depresses enzymatic action. A more complete elimination of enzymatic action is accompHshed by pasteurization. 

First product on market is listed first for each enzyme type. 

The I I cleaning procedures as a whole, compared with household laundering, are characterized by huge variations in the composition of the soils, types of surface to which they adhere, cleaning time available, etc. The optimum choice of enzyme type and dosage level normally has to be established through a cooperation between the customer (end user), manufacturer of the detergent, and enzyme producer. 

Most enzyme treatments of wool are carried out at about 50 °C for 30-60 minutes. The amount of enzyme required depends on the specific enzyme type and its commercial... 

Table 2.3 Mononuclear non-haem iron enzymes classified according both to enzyme type and reaction type. Reprinted with permission from Holm et al., 1996. Copyright (1996) American Chemical Society. 

Enzyme type Enzyme families Examples Reactions catalysed... 

Name of Enzyme Type/M (daltons, Da) Function Absorption Bands, nm (e, mM 1 cm-1) Reduction Potential (mV) Details of EPR spectrum (A x 10-4 crrr1)... 

Glycosidases are rather undemanding in the choice of substrates, which greatly broadens their applications compared to glycosyltransferases. However, they also suffer from several significant drawbacks, such as low regioselectivity and yields. Thus, the choice of an appropriate attitude and an enzyme type remains strongly dependent on the specific application. 

Phosphoinositase C (i.e. phosphoinositide-specific phospholipase C [PLC]) enzymes are found in the vast majority of mammalian cells. Molecular cloning of these enzymes, analysis of their predicted amino acid sequences and immunological cross-reactivity indicate that at least three major forms of the enzyme exist PLC-/I, -8 and -y. Each of these enzyme types is encoded by a distinct gene. More recent experiments using the polymerase chain reaction and molecular cloning have revealed even greater enzyme di-... 

Figure 1.5 Enzyme Types Used in Industrial Biotransformations (based on 134 processes). (Reprinted from Straathof, A.J.J., Panke, S. and Schmid, A. The production of fine chemicals by biotransformations. Curr. Opin. Biotechnol. 2002,13, 548-556 with permission from Elsevier.)...

S. Neuschl and R Menhart, Networks based on enzyme type neurons, in Molecular Electronics Science and Technology, A. Aviram and A. Bross, Eds., Engineering Eoundation, New York, 1989, pp. 167-173. 

This protocol can be nsed as a fu-st-mn attempt at tissue disaggregation. Fnrther experience with the tissue will probably yield insights as to the best enzyme types, enzyme concentration, digestion time, and digestion temperature. 

The diversity among catalases, evident in the variety of subunit sizes, the number of quaternary structures, the different heme prosthetic groups, and the variety of sequence groups, enables them to be organized in four main groups the classic monofunctional enzymes (type A), the catalase-peroxidases (type B), the nonheme catalases (type C), and miscellaneous proteins with minor catalatic activities (type D). 

The action of enzymes is usually very specific. This applies not only to the type of reaction being catalyzed (reaction specificity), but also to the nature of the reactants ( substrates ) that are involved (substrate specificity see p.94). In Fig. B, this is illustrated schematically using a bond-breaking enzyme as an example. Highly specific enzymes (type A, top) catalyze the cleavage of only one type of bond, and only when the structure of the substrate is the correct one. Other enzymes (type B, middle) have narrow reaction specificity, but broad substrate specificity. Type C enzymes (with low reaction specificity and low substrate specificity, bottom) are very rare. 

Enzyme Type Target raw material Expected benefit of use... 

Up to now we have mainly considered macromolecules, but suitably designed smaller molecules may also show features that are usually associated with enzyme-type systems for instance, they may contain a cleft, an intramolecular cavity and display very stable and selective binding. 

McMahon, D. J. and Brown, R. J. 1985. Effects of enzyme type on milk coagulation. J. 

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