We have examined the interaction of hepatic phenylalanine hydroxylase with the phenylalanine analogs, tryptophan and the diastereomers of 3-phenylserine (beta-hydroxyphenylalanine). Both isomers of phenylserine are substrates for native phenylalanine hydroxylase at pH 6.8 and 25 degrees C, when activity is measured with the use of the dihydropteridine reductase assay coupled with NADH in the pr...

ABSTRACT It has been proposed that gravothermal collapse due to dark matter self-interactions (i.e. self-interacting matter, SIDM) can explain the observed diversity of Milky Way (MW) satellites’ central dynamical masses. We investigate process behind this hypothesis using an N-body simulation a MW-analogue halo with velocity-dependent SIDM (vdSIDM) in which low-velocity self-scattering cross-s...

The 〈V/Vmax〉 of the cosmological X-ray flashes detected by Wide Field Cameras on BeppoSAX is calculted theoretically in a simple jet model. The total emission energy from the jet is assumed to be constant. We find that if the jet opening half-angle is smaller than 0.03 radian, the theoretical 〈V/Vmax〉 is less than ∼ 0.4, which is consistent with the recently reported observational value of 0.27...

The glutamate transport system of the bovine renal epithelial cell line NBL-1 was studied. The Km for Na+-dependent glutamate transport was found to be 13.8 + 2.4 ,ltM (Vmax. 365 + 19.2 pmol/3 min per mg) and for Na+-dependent aspartate transport 4.5 + 1.1 ,uM (Vmax. 108 6.3 pmol/3 min per mg). The Km values are in close agreement with those expected for high-affinity Na+-dependent glutamate tr...

In a genetically engineered V79 cell line (XEMd-MZ) expressing rat cytochrome P4501A2 the activity of phenacetin-O-deethylase was determined and compared with freshly isolated rat hepatocytes. In the V79 cells the apparent Km was 0.99 microM (N = 4), compared to the high affinity Km (0.23 microM, N = 4) found in freshly isolated rat hepatocytes, where as the Vmax found in the XEMd-MZ cells (14....

Exposure of murine L929 fibroblasts to ozone caused inactivation of the energy-coupled transport systems for 2-aminoisobutyric acid and Rb+. Ozone induced an increase of the apparent Km for 2-aminoisobutyric acid transport, with a constant Vmax, indicating impairment of the carrier function, rather than a decrease in the number of transport sites. The uptake rate of 2-deoxy-D-glucose, on the ot...

The effect of Tris, Glycine and Tricine on alkaline phosphatase activity was tested at a pH of 8.6, 8.85 and 9.1, using pNPP as substrate. Alkaline phosphatase activity was measured by monitoring the increase in NP absorbance at 420nm using a spectrophotometer. Alkaline phosphatase in Tris buffer at pH 9.1 was found to have the highest activity. MichaelisMenten enzyme kinetic analysis revealed ...

The 〈V/Vmax〉 of the cosmological X-ray flashes detected by WFC/BeppoSAX is calculated theoretically in a simple jet model. The total emission energy from the jet is assumed to be constant. We find that if the jet opening half-angle is smaller than 0.03 radian, off-axis emission from sources at z≤4 can be seen. The theoretical 〈V/Vmax〉 is less than 0.4, which is consistent with the observational...