There are a variety of methods available to calculate the inhibition constant (Ki) that characterizes substrate inhibition by a competitive inhibitor. Linearized versions of the Michaelis-Menten equation (e.g., Lineweaver-Burk, Dixon, etc.) are frequently used, but they often produce substantial errors in parameter estimation. This study was conducted to compare three methods of analysis for th...

Thiol monolayer-protected Au clusters (MPCs) were prepared using dendrimer templates, deposited onto a high-surface-area titania, and then the thiol stabilizers were removed under H2/N2. The resulting Au catalysts were characterized with transmission electron microscopy, X-ray photoelectron spectroscopy, and infrared spectroscopy of adsorbed CO. The Au catalysts prepared via this route displaye...

Prostatic acid phosphatase (EC 3.1.3.2) purified from benign hypertrophic prostate tissue was fractionated by preparative slab isoelectric focusing over a pH gradient of 3.16 to 7.16. Twenty-two of 29 fractions contained enzyme activity. We further examined each active fraction by determining the Michaelis-Menten constant and specific activity. The protein concentration used in the latter deter...

Real time, or quantitative, PCR typically starts from a very low concentration of initial DNA strands. During iterations the numbers increase, first essentially by doubling, later predominantly in a linear way. Observation of the number of DNA molecules in the experiment becomes possible only when it is substantially larger than initial numbers, and then possibly affected by the randomness in i...

Na transport across a preparation of sheep omasum was studied. All tissues exhibited a serosa-positive short-circuit current ( I sc), with a range of 1-4 μeq ⋅ h-1 ⋅ cm-2. A Michaelis-Menten-type kinetic was found between the Na concentration and the I sc(Michaelis-Menten constant for transport of Na = 6.7 mM; maximal transport capacity of Na = 4.16 μeq ⋅ h-1 ⋅ cm-2). Mucosal amiloride (1 mM), ...

Real time monitoring of electrolyte resistance changes during hydrolysis of 4-nitrophenylphosphate (pNPP) by alkaline phosphatase (ALP) bound on paramagnetic-beads was performed into a small dielectric channel. The reaction kinetic fit with a non-competitive substrate-inhibition equation. Michaelis-Menten apparent constant, KM(app), was determined as 0.33±0.06mM and the maximum apparent rate, V...

The involvement of FMO in the N-oxygenation of CLZ was investigated by use of purified FMOs and human liver microsomes that contained the mean amount of immunoreactive FMO3 relative to other human liver microsomal preparations in a liver bank. In the microsomal preparation the involvement of FMO was indicated through enzyme inhibition by methimazole, heat inactivation, and protection against he...