Irradiation enzymes

Total yields of odor concentrates obtained from concurrently and non-concurrently processed, freshly irradiated enzyme-inactivated beef and from stored (6 months) irradiated beef are summarized in Table III. The de-... 

That the radiolysis of meats containing similar proteins and comparable fatty acids involves similar primary and secondary processes leading to a common set of radicals stable at -40°C is shown by the ESR spectra in Figure 12 for irradiated, enzyme-inactivated chicken, beef, ham, and pork [3, 62], These spectra reflect the commonality in radicals derived from the muscle proteins, myosin and actin, and fi-om the constituent triglycerides, which have slightly different fatty acid compositions. The minor consequences of this compositional... 

Figure 15. Normali2 d yield of hexane as a function of fat content in irradiated enzyme-inactivated muscle foods, expressed as nanograms per gram and normalized to 10 kGy of dose applied at -30°C. Adapted from Taub et al. [14] with permission.

Irradiation. Although no irradiation systems for pasteurization have been approved by the U.S. Food and Dmg Administration, milk can be pasteurized or sterilized by P tays produced by an electron accelerator or y-rays produced by cobalt-60. Bacteria and enzymes in milk are more resistant to irradiation than higher life forms. For pasteurization, 5000—7500 Gy (500,000—750,000 tad) are requited, and for inactivating enzymes at least 20,000 Gy (2,000,000 rad). Much lower radiation, about 70 Gy (7000 tad), causes an off-flavor. A combination of heat treatment and irradiation may prove to be the most acceptable approach. 

Polydioxanone (PDS) is completely elirninated from the body upon absorption. The mechanism of polydioxanone degradation is similar to that observed for other synthetic bioabsorbable polymers. Polydioxanone degradation in vitro was affected by gamma irradiation dosage but not substantially by the presence of enzymes (39). The strength loss and absorption of braided PDS, but not monofilament PDS, implanted in infected wounds, however, was significantly greater than in noninfected wounds. 

MetaHoelement complexes may be useful for the post-irradiation treatment of radiation injury, based on the observation that several of these compounds accelerate recovery of, among other things, lympho/hemopoiesis. Preirradiation Mn2(0)(DIPS)g increases the survival of y-irradiated mice (103). Treatment of mice that have been exposed to an LD q q dose of y-rays plus Mn2(0)(DIPS)g either 1 or 3 h after irradiation also increases survival, which supports the hypothesis that this compound is an effective radiorecovery agent (105). Again, this increase in survival may result from the resynthesis of radiation-depleted Mn-dependent enzymes that facHitate the recovery of immunocompetence and tissue repair, as reported for Cu(II)2(DIPS)4. 

The proteolytic enzymes, trypsin, chymotrypsin, and chymoral [8076-22-0] in combination, have been used for the treatment of post-operative hand trauma, athletic injuries, and sciatica (214—216). Trypsin has also been used successfully in treating hyaline membrane disease of newborn babies, a condition usually fatal without treatment (217). Immobilized preparations of trypsin are useful in treating acute radiation cystitis following pelvic x-irradiation therapy (218). 

Once mounted in the diffractometer, the crystal is irradiated with X rays, usually so-called Cu/Cg radiation with a wavelength of 0.154 nm. When the X rays strike the enzyme crystal, they interact with electrons in the molecule and are scattered into a diffraction pattern, which, when delected and visualized, appears as a scries of intense spots against a null background. 

Plants are constantly subject to adverse environmental conditions such as drought, flooding, extreme temperatures, excessive salts, heavy metals, high-intensity irradiation and infection by pathogenic agents. Because of their immobility, plants have to make necessary metabolic and structural adjustments to cope with the stress conditions. To this end, the expression of the genetic programme in plants is altered by the stress stimuli to induce and/or suppress the production of specific proteins which are either structural proteins or enzymes for specific metabolic pathways. 

Punnonen, K., Puntala, A., Jansen, C.T. and Ahotupa, M. (1991a). UVB irradiation induces lipid peroxidation and reduces antioxidant enzyme activities in human keratinocytes in vitro. Acta Dermato-Venereol. 71,... 

Nabors CJ, Berliner DL, Stevens W. 1967. Preliminary comparison of the effects of241 Am and 239Pu on serum enzymes. In Research in radiobiology Annual report of work in progress in the Internal Irradiation Program. Utah Radiobiology Division of the Department of Anatomy, University of Utah College of Medicine, 97-127. Contract No. AT(11-1)-119. 

Studies on the active agent of the yeast extract have shown it to be nondialyzable, heat labile, and inactivated by trypsin and chymotrypsin as well as silver ions and p-hydroxymercuribenzoate.(7l) These and other properties suggest that the active agent is an enzyme. Sedimentation studies have shown that the yeast photoreactivating enzyme combines with UV-irradiated DNA, in which condition it is more resistant to heat inactivation and inactivation due to silver ions and p-hydroxymercuribenzoate.<75) The... 

In the latter case, electron uptake occurs after decarboxylation of the ketoacid via Fe3+, which is able to take up electrons in strongly oxidized regions of the black-band iron sediments. Fe-ions act catalytically on the process of thioester formation, which can then occur without the help of enzymes. Thus, it was solar UV irradiation which carried the prebiotic thioesters across the energy threshold. 

Superoxide Dismutase. Again, only electron-capture is important on irradiation (78). For the Cu-Zn enzyme, Cu is converted into Cu form. In the presence of oxygen, 02 is formed in competition with Cu, and on annealing reacts to re-form Cu. Thus radiolysis has proven to be a useful method for checking the mechanism of action of this dismutase. The conclusion is that the somewhat disputed mechanism [21,22] is probably correct. 

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