Journal: The Journal of Biological Chemistry

Article Title: Unexpected Activity of a Novel Kunitz-type Inhibitor

doi: 10.1074/jbc.M116.724344

Figure Lengend Snippet: Plot of F. hepatica cathepsin L1 proteolytic activity with the substrate Z-Leu-Arg-NHMec, as a function of inhibitor concentration for rFhKT1 ( solid circles ) and rFhKT1Leu 15 /Arg 15 ( clear circles ). The curves represent the best fit to the Morrison equation ( solid line = rFhKT1; dashed line = rFhKT1Leu 15 /Arg 15 ). Error bars indicate standard deviation of three separate experiments.

Article Snippet: K i values were determined using the Morrison equation for tight-binding inhibition (built into GraphPad Prism 5.0).

Techniques: Activity Assay, Concentration Assay, Standard Deviation

Journal: Journal of Lipid Research

Article Title: Quantification of 3-ketodihydrosphingosine using HPLC-ESI-MS/MS to study SPT activity in yeast Saccharomyces cerevisiae [S]

doi: 10.1194/jlr.D078535

Figure Lengend Snippet: Inhibition of yeast microsome SPT activity by myriocin. Two hundred micrograms of yeast microsomes (∼0.0125 μM SPT) were incubated with 0.95 mM L-Ser (3,3-D2) in the presence of 0–128 nM myriocin for 5 min before stopping the reaction with NH4OH followed by lipid extraction and HPLC-ESI-MS/MS to quantify the 3KDS (+2D) products. Enzyme activity, which was measured by SPT velocity, was plotted against myriocin concentration using the Morrison equation function from GraphPad Prism 5. The estimated Ki for myriocin is 10.3 ± 3.2 nM.

Article Snippet: Enzyme activity, which was measured by SPT velocity, was plotted against myriocin concentration using the Morrison equation function from GraphPad Prism 5.

Techniques: Inhibition, Activity Assay, Incubation, Extraction, Tandem Mass Spectroscopy, Concentration Assay