HE GENETICS of coat color pigmentation in the guinea pig have been exT tensively analyzed by WRIGHT (1916, 1917, 1925, 1927). These studies have been supplemented by various attempts to discover the underlying inherited physio . logical processes, either by quantitative determinations of pigmented end product (E. S. RUSSELL 1939; HEIDENTHAL 1940; WRIGHT and BRADDOCK 1949; WRIGHT 1949) or by ass...

Polyphenol oxidase (PPO) from tomatoes was extracted and partially purified through  (NH4)2SO4 precipitation, dialysis and ion exchange chromatography. The activity of polyphenol oxidase was investigated in solanum lycopersicum. Spectrophotometric method was used to assay the enzyme activity and the kinetic constants - maximum enzyme velocity (Vmax) and Michealis - Menten constant (Km). Of the ...

N-(3,5-Dihydroxybenzoyl)-6-hydroxytryptamine (2) was a novel inhibitor of L-3,4-dihydroxyphenylalanine (DOPA) oxidase activity of human HMV-II melanoma tyrosinase. The IC₅₀ values for 2 and three reference compounds, N-(3,5-dihydroxybenzoyl)serotonin, 6-hydroxyindole, and kojic acid, were 9.1, 842, 22, and 310 µM, respectively, indicating that the 6-hydroxyindole moiety was more effective than ...

KOCAQALISKAN I., DEMIR Y. & KABAR, K. 1995. A study on polyphenol oxidase activity during seed germination. Phyton (Horn, Austria) 35 (1): 37-43. English with German summary. In this work, polphenol oxidase (PPO) activities, when used four different substrates (dopa,catechol,caffeic acid, tyrosine) oxidizing activities, during seed germination of six different plants were studied in the embryos...

Banisteriopsis caapi (B. caapi) contains harmine, harmaline, and tetrahydroharmine, has monoamine oxidase inhibitory activity, and has reported antiparkinsonian activity in humans when imbibed as a tea; however, its effects are poorly documented. For this reason, motor function was assessed in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated common marmosets following administration of B. c...

Betalains are a group of nitrogen-containing pigments that color plants in most families of Caryophyllales. Their biosynthesis has long been proposed to begin with hydroxylation of L-tyrosine to L-DOPA through monophenolase activity of tyrosinase, but biochemical evidence in vivo remains lacking. Here we report that a Group 4 catalase, catalase-phenol oxidase (named as AcCATPO), was identified,...

This study reports depigmenting potency of 1,3-selenazol-4-one derivatives, which would be based upon the finding of direct inhibition to mushroom tyrosinase. 1,3-Selenazol-4-one derivatives exhibited inhibitory effect on dopa oxidase activity of mushroom tyrosinase. In this study, inhibitory effects of six kinds of 1,3-selenazol-4-one derivatives (A, B, C, D, E and F) on mushroom tyrosinase we...

The neuroendocrine [amine precursor uptake (decarboxylase)] properties of small (oat) cell lung cancer (SCC) have suggested that this neoplasm may have a separate histogensis from the other major types of human lung tumors. We now report that a key element of this concept, L-dopa decarboxylase activity, is present in surgical and autopsy tissues from all forms of lung cancer. Values are highest...

Phenoloxidase from Artemia sinica (AsPO) was purified by Superdex 200 gel-filtration and Q Sepharose fast flow ion-exchange chromatography, and its properties were characterized biochemically and enzymatically by using L-dihydroxyphenylalanine (L-DOPA) as the specific substrate. Results showed that AsPO was isolated as a monomeric protein of 125.5 kDa in molecular mass. The optimal pH value and...

The influence of various enzyme inhibitors on the cardiovascular effects of L-dopa (methylester) has been studied to determine the sites of action of the drug or a responsible metabolite. L-Dopa, 10 mg/kg, iv, had minor early effects on heart rate and blood pressure in normal dogs, but in animals with inhibition of monoamine oxidase (MAO), it caused tachycardia and severe hypotension of gradual...