Methemoglobin level in infants and its relation to nitrate content in drinking water

Methemoglobin level in various infant age groups was determined Infant [1-18 months of age] living in Al-Haram area with a nitrate concentration in drinking water up to 65mg/L [as NO3-N] were examined for their methemoglobin level. Their methemoglobin levels ranged from 2.23% -10.33% of their total hemoglobin, compared to 0.35% -1.85% in case of controls.The increase in methemoglobin was associated with a low hemoglobin level. This was more prominent in infants under 6 months of age. Significant decrease in methemoglobin levels were noticed after administration of Vitamin C

Kinetic behavior of catalase immobilized by covalent coupling

In this work, the partition effects due to the changes in the microenvironment of catalase by immobilization was studied in the absence of any diffusional resistance. The pH activity profiles were done for both soluble and immobilized catalase. Catalase was immobilized on nonporous glass beads, so the internal diffusional resistance is not considered. The external diffusion effect is also minimized by the continuous stirring through the enzyme assay. The Km value for the immobilized enzyme was also determined at different ionic strengths. The results showed a constant Km and suggested that the microenvironmental changes due to immobilization of catalase by the applied method are negligible and that any kinetic parameter determined is the true intrinsic parameter and not an apparent one

Preparation and determination of immobilized catalase

Bovine liver catalase was immobilized on nonporous glass beads by covalent bonding. Higher concentration of catalase in the immobilizing solution resulted in higher activities in the immobilized sample. This was found to be true only up to certain limit. The immobilized enzyme activity was determined using the oxygen evolution from 0.01 M hydrogen peroxide. Linear rates were observed during the first 50 seconds because a negligible proportion of the substrate is used up and because enzyme inactivation is too slow to affect the initial rate