Active-site titration of enzymes at high concentration. Application to myosin ATPase

Evidence for Histidine at the Active Site of Myosin A.

Decavanadate binding to a high affinity site near the myosin catalytic centre inhibits F-actin-stimulated myosin ATPase activity.

Decameric vanadate (V(10)) inhibits the actin-stimulated myosin ATPase activity, noncompetitively with actin or with ATP upon interaction with a high-affinity binding site (K(i) = 0.27 +/- 0.05 microM) in myosin subfragment-1 (S1). The binding of V(10) to S1 can be monitored from titration with V(10) of the fluorescence of S1 labeled at Cys-707 and Cys-697 with N-iodo-acetyl-N'-(5-sulfo-1-napht...

ATP turnover by individual myosin molecules hints at two conformers of the myosin active site.

Coupling of ATP hydrolysis to structural changes in the motor domain is fundamental to the driving of motile functions by myosins. Current understanding of this chemomechanical coupling is primarily based on ensemble average measurements in solution and muscle fibers. Although important, the averaging could potentially mask essential details of the chemomechanical coupling, particularly for mix...

Evidence of Tryptophan at or near Active Site of Glucoamylase I of Arthrobotrys amerospora

Arthrobotrysamerospora (ATCC 34468) produced glucoamylase in a semi-synthetic medium containing starch as a sole carbon source. Polyacrylamide gel electrophoresis of crude glucoamylase showed three isoenzymes. They were designated as glu I, glu II and glu III according to their electrophoretic mobility. These iso-glucoamylases were purified by column chromatography using DEAE-Sephadex A-50. The...

Discovery of active site of vinblastine as application of nanotechnology in medicine

Objective(s): Vinblastine is antimitotic, anticancer medicine that disturbs normal microtubule formation and favours depolymerisation. Structural study and finding the active site of vinblastine are the targets of this research.   Materials and Methods: Vinblastine was optimized in vacuum and then in different solvents by Density Functional Theory (DFT) method. Nuclear Magnetic Resonance (NMR) ...