On the nature and mode of action of the copperprotein, tyrosinase

Molecular Diseases of Connective and Vascular Tissues. II. Amine Oxidase Inhibition by the Lathyrogen, β-Aminopropionitrile*

“…This seems unlikely in view of the results obtained with polyphenoloxidase and uricase. Even though these enzymes represent diverse types of copper oxidase activity and both are inhibited by copper chelators (Dressier and Dawson, 1960;Mahler et al, 1955), the presence of 100 mM BAPN does not alter the activity of either enzyme. These data indicate that BAPN is not an avid chelator of enzyme copper and suggest that additional factors are involved in the binding of BAPN to the active site of amine oxidase.…”

Antioxidation and Tyrosinase Inhibition of Polyphenolic Curcumin Analogs

“…Tyrosinase (EC 1.14.18.1), also known as polyphenol oxidase, is a multifunctional copper-containing enzyme widely distributed in nature. 1) It catalyzes two distinct reactions of melanin biosynthesis: the o-hydroxylation of monophenols to o-phenols (monophenolase activity), and the oxidation of o-phenols to o-quinones (diphenolase activity). 2) These quinones are highly reactive compounds that can polymerize spontaneously to form melanins, which determine the color of mammalian skin and hair.…”

“…. Yield 72%, mp 206-208 C 1. H NMR (DMSO-d6, 300 MHz) (ppm): 9.80 (brs, 2H, -OH), 7.21 (d, J ¼ 8:1 Hz, 2H, ArH),6.73 (s, 2H, -CH=),6.61 (d, J ¼ 8:1 Hz, 2H, ArH),6.47 (s, 2H, ArH), 3.68 (s, 6H, -OCH 3 ), 2.81 (m, 4H, -CH 2 -C-CH 2 -),1.74 (m, 2H, C-CH 2 -C).…”

Influence of pH and Ionic Strength on the Adsorption of Copper and Zinc in Bentonite Clay

“…In general all trace elements are toxic to plants if they are present in concentrations above normal. Two of the most important micronutrients are Cu and Zn, occurs in the soil principally as Cu 2+ and Zn 2+ ions adsorbed by clay minerals or tied up by organic matter 14 , copper play a role in plant growth as an enzyme activator, also it is important in protein metabolism and may be associated with chlorophyll formation [15][16][17][18][19] . Zinc acts either as a metal component of enzymes or as a functional, structural or regulatory cofactor of a large number of enzymes, it is well established that zinc deficiency is associated with an impairment of carbohydrate metabolism and protein synthesis 20 .…”