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 ...

Abstract. Ectoenzymatic activity, prokaryotic heterotrophic abundances and production were determined in the Mediterranean Sea. Sampling was carried out sub-surface, deep chlorophyll maximum layer (DCM), core of Levantine intermediate waters deeper part mesopelagic layers. Michaelis–Menten kinetics assessed using a large range concentrations fluorogenic substrates (0.025 to 50 µM). As consequen...

BSC-1 kidney epithelial cells derived from the African green monkey are known to express a Na+HCO3- symport (Jentsch, T. J., Schill, B. S., Schwartz, P., Matthes, H., Keller, S. K., and Wiederholt, M. (1985) J. Biol. Chem. 260, 15554-15560). In the present work, 4,4-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS)-sensitive 22Na+ uptake into confluent monolayers of BSC-1 is measured in the pr...

Physicochemical and immunologic properties of 6-aminolevulinate (ALA) dehydratase in human K562 erythroleukemia cells were examined. ALA dehydratase activity was found to increase in K562 cells after treatment with butyric acid or selenium oxide. Enzyme activity in untreated K562 cells was comparable to that in normal adult erythrocytes but was increased threeto six-fold in K562 cells treated w...

Physicochemical and immunologic properties of 6-aminolevulinate (ALA) dehydratase in human K562 erythroleukemia cells were examined. ALA dehydratase activity was found to increase in K562 cells after treatment with butyric acid or selenium oxide. Enzyme activity in untreated K562 cells was comparable to that in normal adult erythrocytes but was increased threeto six-fold in K562 cells treated w...

Kinetic studies were carried out on alkaline phosphatase (ALP) extracted from the liver of Agama agama lizard. Incubation of ALP extract with para – nitrophenyl phosphate formed the basis for the determination of enzyme activity. Spectrophotometric method was used to assay the enzyme, and the kinetic constants: Maximum velocity (Vmax) and Michaelis Menten constant (Km) were calculated. The Km a...

Potassium uptake rate of two cotton (Gossypium hirsutum L.) varieties viz., NIBGE-2 and MNH-786 was investigated in nutrient solution culture having deficient K @ 0.3 mM and deficient K+ Na @ 0.3 +2.7 mM. Depletion of K from solution was monitored over a period of 24 h at regular time intervals after 0, 0.5, 1.0, 1.5, 2, 3, 4, 5, 6, 8, 10, 12 and 24 h to estimate K uptake kinetics of the roots ...

A reaction system of Michaelis-Menten enzyme on single substrate can be characterized by the initial substrate concentration before enzyme action (S0), the maximal reaction rate (Vm) and Michaelis-Menten constant (Km), besides some other required parameters. The estimations of S0, Vm and Km can be used to measure enzyme substrates, enzyme activities, epitope or hapten (enzyme-immunoassay), irre...

Understanding the mechanism of brain glucose transport across the blood-brain barrier is of importance to understanding brain energy metabolism. The specific kinetics of glucose transport have been generally described using standard Michaelis-Menten kinetics. These models predict that the steady-state glucose concentration approaches an upper limit in the human brain when the plasma glucose lev...