Enzymatic decomposition

Cyclodextrins (CDs) are inclusion compounds formed by enzymatic decomposition of starch to the cyclic oligosaccharides containing six to eight... 

Most probably some fraction of the peptides appearing in urine represents small quantities of peptide hormones, such as vasopressin, oxytocin, glucagon, and the melanocyte-stimulating hormone, the occurrence of which in small amounts in normal urine has been occasionally reported. As the specific enzymatic decomposition of these hormones takes place... 

Julkunen-Tiitto R, Meier B. The enzymatic decomposition of salicin and its derivatives obtained from salicaceae species. J Nat Prod 1992 55 1204—1212. 

Meyer-Reil, L.-A., 1981. Enzymatic decomposition of proteins and carbohydrates in marine sediments methodology and field observations during spring. Kieler Meeresforsch., Sonderh., 5 311-317. 

Gajewski, A. J., and R. J. Chrost. 1995. Production and enzymatic decomposition of organic matter by microplankton in a eutrophic lake. Journal of Plankton Research 17 709—728. 

Chrost, R. J., R. Wcislo, and G. Z. Halemejko. 1986. Enzymatic decomposition of organic matter by bacteria in an eutrophic lake. Archiv fur Hydrobiologie 107 145-166. 

Donkin, S.G., Eiteman, M.A., Williams, P.L. Toxicity of glucosinolates and their enzymatic decomposition products to Caenorhabditis elegans. J Nematol 1995 27 258-262. 

All of the three phases of enzymatic methods were dominated by proteolytic enzymes. However, nonproteolytic ones were also addressed for special purposes to indirectly assist proteolysis, for example, by providing access to proteins to be hydrolyzed through the enzymatic decomposition of the matrix constituents. At the same time, the use of nonproteolytic enzymes might be promoted in the future to study the possibly nonprotein-associated Se macromolecules which have already been observed in the case of numerous real samples, for example, edible mushroom [58, 80], but so far have never been investigated in detail. 

The determination of the purine-nucleotide metabolites xanthine, hypox-an thine, and inosine by biosensors is of special interest for the estimation of meat or fish freshness. After the death of a fish, adenosine triphosphate (ATP) in the fish tissue is quickly degraded to inosine monophosphate (IMP). Further enzymatic decomposition of IMP leads to the accumulation of hypoxan thine (Hx), which is used as an indicator of fish freshness. To quantify these compounds with biosensors, it is possible to perform amperometric measurements of the generated hydrogen peroxide or the consumed oxygen according to the following enzymatic reactions ... 

This chapter gives an overview of decomposition methods and recent developments and applications of the decomposition of different materials. Other sample preparation methods, such as chemical extraction and leaching, solubilization with bases, enzymatic decomposition, thermal decomposition, and anodic oxidation, are beyond the scope of this contribution and are not discussed. 

Solutions containing active enzymatic proteins (protease, lipase, trypsin, pepsin, prophase, or cellulase) or their mixtures, adjusted to the nature of the matrix of the solid material of biological origin [79, 83, 84]. The aim of the procedure is to break up proteins, polysaccharides, or fat chains and release the constituent amino acids, sugars, or short aliphatic chains. Enzymatic decomposition of the matrix can be considerably enhanced by application of ultrasound the process can, for example, increase the efficiency of disintegration of cell walls in yeast and thus improve the recovery of selenium by as much as 20 % [85]. 

Fig. 1 Inhaled drug in a carrier can exist in the slow clearing pulmonary compartment (Pi) without mucociliary clearance or in the faster clearing pulmonary compartment with mucociliary clearance (P2), tracheobronchial compartment (TB) or gastrointestinal tract (GI). When the drug is released into these compartment (the released drug is represented by italicized letters Pi, P2, TB, GI), it can be absorbed into the bloodstream, or it can be removed by non-productive pathways such as mucociliary clearance represented by the vertical arrows, or chemical and enzymatic decomposition. Large molecules may also enter lymphatics before they appear in the blood stream. (The detailed model was described while the simplified three-compartment model represented by the ellipses is from Refl l)...

Generally, low intensity ultrasound can increase the activity of enzymes and immobilized enzymes, or can improve the metabolism of cells by the improvement of mass transfer to substrates. One example is the enzymatic decomposition of mandelonitrile by mandelonitrile lyase in di-isopropyl ether which has been accelerated 10-fold by ultrasound [66], The mandelonitrile lyase was not denatured by 30 kHz operating at 0.5 W cm-2 and pulsed at 15 s per min. 

PHB The PHB is extracted from the dried cells by means of suitable chlorinated solvents and subsequent precipitation of the PHAs. As an alternative, the cell components can be dissolved in an appropriate oxidizing solvent or by using enzymatic decomposition of the cells including the cell components and sonic oscillation. However, enzymatic decomposition should be preferred taking into account the risks of using chlorinated solvents. 

In general, both P2HAs and P3HAs, are subjected to acid-based catalyst hydrolytic decomposition in a low-temperature range, and only biotechnologically produced PHAs are subjected in addition to enzymatic decomposition due to extracellular enzymes. Some microorganisms excrete extracellular depolymerases to degrade microbial PHAs and to utilize the decomposed compounds as nutrients. 

PHB Under optimum conditions, in the accumulation phase during the fermentation process, the rate of the enzymatic degradation of this amorphous PHB is extremely fast, within a few hours. In contrast to this, extracted or processed, partially crystalline PHB is attacked relatively slowly over periods of weeks. The enzymatic decomposition, for example, of the PHB test specimen, leads to a slow surface erosion, while the volume body remains unchanged for some time, so the whole weight and the properties change slowly. The enzymatic degradation occurs at the surface of the PHB material and the rate of the surface erosion is strongly dependent on both the structure and the composition. 

A pure hydrolytic decomposition of hydrophobic PHB is, in contrast to the enzymatic decomposition under the same experimental conditions, about 2-3 times slower, but increases with growing pH-value and temperature. Under high-temperature conditions, above the melting point, the PHB is subjected to the formation of linear oligomers as a result of ester cleavage and/or a jS-elimination, and this resulted in crotonic acid. 

Inorganic pyrophosphate may be considered as a particular case of a phosphate monoester. The enzymatic decomposition of pyrophosphate by inorganic pyrophosphatase (Table 13-6, entry 10) can be used to drive a multienzyme synthesis (see1351). 

---