Enzymatic synthesis active materials

R Hischmann, RF Nutt, DF Veber, RA Vitali, SL Varga, TA Jacob, FW Holly, R Denkewalter. Studies on the total synthesis of an enzyme. V. The preparation of enzymatically active material. J Am Chem Soc 91, 507, 1969. 

Adlercrentz, P, On the importance of the snpport material for enzymatic synthesis in organic media. Snpport effects at controlled water activity, Eur. J. Biochem., 199, 609-614, 1991. 

This review summarizes the recent results in the preparation of well-defined chiral polymers from optically inactive monomers. To date, optically active polycondensates based on non-natural monomers are still a curiosity in polymer chemistry. Expanding the catalytic toolbox in polymer chemistry by adopting methods from chemo-enzymatic synthesis may enable easy access to chiral polymers and allow the exploration of the added value of chirality in materials. Moreover, chemo-enzymatic approaches have the potential to further enhance macromolecular complexity and hence allow to access new materials with applications envisaged in nanomaterials and biomedical materials. 

Amino acids have been produced by chemical synthesis, extraction from protein hydrolysates, enzymatic synthesis, and microbial fermentation. The chemical synthesis includes artificial synthesis from chemical starting material and usually produces an enantiomeric mixture of amino acids which will further require a step of optical resolution. Only a few amino acids are produced economically by chemical synthesis owing to the high production cost. Glycine and methionine are the two amino acids that are manufactured chemically and widely used in animal feeds. Glycine is manufactured from ammonia and formaldehyde and does not have a stereo chemical center or is achiral. For methionine, animals have a d-amino acid oxidase and transaminase activity that can convert the D form to L form of the amino acid. Otherwise DL methionine is acetylated to produce L-methionine. 

Crout has recently shown that this approach can provide good (up to 61%) yields if the reaction is performed at an elevated temperature (50 °C) and time is spent in determining the optimum water activity to be used for the enzyme under study [17]. This can be achieved either by directly adjusting the alcohol/water ratio or by varying the concentration of a co-solvent. This approach can therefore provide useful syntheses of simple glycosides as starting materials for chemical or enzymatic synthesis. 

When the approach of chiral auxiliary is used to generate a chiral center in a molecule, enzymatic resolution has become a frequently used methodology for the synthesis of biologically interesting materials with high optically active forms. 

An acceleration of protein turnover by thyroxine also has been shown, implying that the hormone may alter various processes by a specific effect on synthesis of certain key proteins Involved in enzymatic reactions, Thus, not only does thyroxine increase the rate of formation of new protein material, hut it also may be responsible for the transformation of non-en/.ymalically active protein Into protein with enzymatic activity. The hormone has also been shown to be capable of acceleration of the synthesis of urea cycle enzymes and probably is essential for the production of a... 

Stereospecific 2,3-epoxidation of squalene. followed by a non-concerted carbocationic cyclization and a seiies of carbocationic rearrangements, forms lanosterol (26) in the first steps dedicated solely toward steroid synthesis. Cholesterol is the principal starting material for steroid hormone biosynthesis ill animals. The cholesterol biosynthetic pathway is composed of at least 30 enzymatic reactions. Lanosterol and squalene appear to he normal constituents, in trace amounis. in tissues that are actively synthesizing cholesterol,... 

Active and excipient chemical ingredients used in drug products may therefore be considered as BPCs. These materials can be made by chemical synthesis, fermentation, enzymatic reactions, recombinant DNA, recovery from natural materials, or a combination of the above. 

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