This study characterizes microsomal heme oxygenase, a previously undescribed enzyme which catalyzes the oxidation of heme at the cr-methene bridge to form biliverdin. This step is then coupled with soluble NADPH-dependent biliverdin reductase to form bilirubin; microsomal heme oxygenase is rate-limiting in this pathway. By all analytical criteria, the product of this reaction is bilirubin. Most...

Objective(s): The goal of this study was assessing the prophylactic effect of exercise and its role as an adjuvant therapy on level of cytokines involved in angiogenesis in estrogen-dependent breast cancer. Materials and Methods: Forty female BALB/c mice were randomly assigned to exercise-tumor-exercise (ETE), exercise-tumor-rest (ETR), rest-tumor-exercise (RTE) and rest-tumor-rest (RTR) groups...

The effect of binding of amitriptyline to human liver microsomes and to microsomes from human B-lymphoblastoid cells on the estimation of enzyme kinetic parameters describing N-demethylation to nortriptyline was investigated using a combination of microsomal binding and in vitro enzyme kinetic studies. Quantitative binding in both matrices increased with higher microsomal protein concentrations...

Enzymatic bioelectrochemistry represents the marriage of electrochemistry and enzymatic biocatalysis, has led to important applications for biosensors, biofuel cells, bioelectrocatalysis. Enzyme immobilization is basis bioelectrochemistry, as itself determines enzyme/material interface thus electrochemical performance. Amongst range methods enzyme immobilization, one-step approaches feature rap...

The kinetic properties of the rat liver microsomal ATPase, with respect to Na(+), K(+) and AT P requirements were examined. Presence of Na(+) and K(+), or both hardly caused any stimulation of the enzyme activity. The Km values for Na(+) and K(+) were substantially low (0.32 and 0.05 mM, respectively), compared to those reported for the Na(+), K(+) ATPasesfrom different tissues. Substrate kinet...

Sendai virions contain an enzyme which catalyzes the incorporation of ribonucleotides into ribonucleic acid (RNA). Enzyme activity was optimal at pH 8.0 and 28 C; otherwise conditions were similar to those reported for Newcastle disease virion (NDV) RNA polymerase. The initial rate of RNA synthesis by the Sendai virion enzyme was about 10 pmoles per mg of protein per hr, but after 3 hr of incub...

We demonstrate for the first time the combination of human liver cytosol and microsomal enzyme sources into an electro-optical array to screen for reactive metabolites produced in multi-enzyme metabolic processes.

Squalene epoxidase activity has been studied in cell-free preparations of Chinese hamster ovary (CHO) cells and rat liver. In contrast to rat liver microsomal squalene epoxidase, the enzyme of CHO cells is only slightly activated by the autologous cytosolic fraction, whereas phosphatidylglycerol or rat liver cytosolic preparations are potent stimulators of this enzyme. Triton X-100, a known sti...

The poly(p-phenylene vinylene) derivative MEH-PPV is known to exist as two morphologically distinct species, referred to as red phase and blue phase. We show here that the transition from the blue phase to the red phase is a critical phenomenon that can be quantitatively described as a second order phase transition with a critical temperature T(c) of 204 K. The criticality is associated with th...