• Journal of Sericultural and Entomological Science
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• v.41 no.2
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• pp.116-121
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• 1999

This study was aimed to explain the essence of Hydroxylammonium hydrochloride(H.A.) effect on degummed silk fiber increasing the colour sites due to oxime generating reaction. H.A. in aqueous solution caues to increase the amount of [H+] and reduce pH values as the concentration of H.A. increases. The rate of [H+] absorption of silk fiker in acidic solution differs on the basic of solution pH and shows a specific uptake in each pH, the lower the pH of solution, the higher the amount [H+] absorption. The pH of solution after treating of silk fiber in H.A. and HCl, showed more remaining [H+] in H.A. solution due to [H+] releasing under the procedure of oxime production. Also it was revealed that in higher concentration of H.A. the reaction for oxime fixation in silk fiber carried out stonger and as a result the bigger gap with acid uptake curve appeared. FT-IR analysis of silk fiber treated with H.A. revealed the creating of intermolecular H-bond at the 2,981-2.930 cm-1, which was not appeared for nontraeted silk fibers and shows H-bond between N-OH group in oue chain and C=) group in another chain of silk protein. Colourimetry of dyed silk fiber after H.A. tratment showed that the silk fiber treated with the high concentration of H.A. compare to low concentration, absorbed more dyeing molecules and so Showed less percontage of Whiteness.

• Bulletin of the Korean Chemical Society
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• v.22 no.4
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• pp.362-366
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• 2001

To show the effects of metallothionein (MT) on the activity of enzymes involved in the removal of reactive oxygen species, MT has been added to the assay systems of superoxide dismutase (SOD), catalase and peroxidase. We have used assay systems of SOD based on NADPH oxidation and nitrite formation from hydroxylammonium chloride as an assay of superoxide breakdown rate. The two assay systems showed different results at the high concentration of MT. MT showed the scavenging of superoxide in the SOD assay system in the presence and absence of SOD. MT added to the SOD assay system behaved as an activator of SOD, but apo-MT behaved as an inhibitor. When MT was added to the assay system in the presence of a fixed amount of SOD, the breakdown rate of superoxide increased. The effects of MT on the decomposition of hydrogen peroxide and the activity of catalase and peroxidase decomposing hydrogen peroxide were evaluated. MT decreased the activities of catalase and peroxidase. We have concluded that the function of MT as an antioxidant might effect the level of superoxide scavenging and not the level of hydrogen peroxide.

• Journal of environmental and Sanitary engineering
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• v.21 no.1 s.59
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• pp.52-57
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• 2006

Metallothioneins(MTs) belong to the class of low molecular weight proteins. Recently, it has been suggested that MTs may playa direct role in cellular defense against oxidative stress by functioning as antioxidants. Oxidative damage to different cellular components makes a major contribution to many pathogenenesses. Several studies have demonstrated that MT is able to quench a wide range of reactive oxygen species at a higher efficiency than other well known antioxidants such as superoxide dismutate(SOD). The present study was designed to evaluate the effect of MT on the activities of the reactive oxygen species removal system. MT showed the scavenging of superoxide in the SOD assay system in the presence or absence of SOD. When MT was added to nicotinamide adenine dinucleotide phosphate(NADPH) oxidation system in presence of fixed amount of SOD increase the breakdown rate of superoxide. When MT was added to the system that form nitrite from hydroxylammonium chloride, the formation of nitrite was inhibit. We concluded that the function of MT as antioxidant might have an effect on the level of superoxide scavenging.