The effects of increasing concentrations of boron (0, 0.1, 1, 10 and 20 mM) as boric acid on the rate of germination and polyphenol oxidase activities in embryo and endosperm tissues of maize seeds (Zea mays L. cv. Arifiye) were studied. The germination percentage of maize seeds was not affected by boron concentrations up to 10 mM, and decreased by 20 mM. Distilled water and lower boron concent...

Article history: Received 11 February 2010 Received in revised form 29 March 2010 Accepted 14 June 2010

PEROXIDASE, the enzyme which induces the oxidation of guaiacum and other oxidisable substances by hydrogen peroxide, is known to be present in nearly all living plant cells. Many plants, moreover, are able to cause the blueing of guaiacum without the addition of hydrogen peroxide; these have been considered to contain a direct oxidase, phenolase or laccase. Bach and Chodat consider such an enzy...

Green tea (C. sinensis) extract (GTE) dose dependently produced reversal of despair in normal, reserpinised and diabetic mice, thereby demonstrating an antidepressant effect. Although the exact mechanism is yet to be explored, the possible inhibition of catechol-o-methyl transferase and monoamine oxidase enzymes may be responsible for antidepressant activity of GTE.

A copper-containing protein resembling in its optical and EPR spectra stellacyanin from latex was isolated from spinach leaves. The protein oxidizes ferrocyanide and catechol. The activity was highest at acidic pH. It was shown that similar proteins isolated from cucumber and squash also possess the oxidase activity to ferrocyanide.

The enzyme catechol oxidase plays a key role in the manufacture of black tea. It is responsible for most, if not for all, of the chemical reactions which take place during tea fermentation. For this reason much research has been, and con tinues to be, devoted to the elucidation of the properties of this enzyme. Until recently, it was generally believed that the enzyme was insoluble in nature an...

We report the use of triazacyclophane (TAC)-scaffolded amino acids as a structural mimic for 3-histidine metal-binding sites in metalloproteins, especially for the mimicry of type-3 copper binding sites as are present in hemocyanin, tyrosinase and catechol oxidase.

Adrenomedullary cells, after fixation with OsO(4), are filled with well formed granules which are considered to represent their catechol amine content. The submicroscopic appearance of these cells was studied in reserpine-treated rats during the late phase of catechol amine depletion and during the period of its restoration. At 3 days after the beginning of reserpine treatment, the granules app...