A kit for screening a compound for enzyme inhibition activity using a microfluidic device, the microfluidic device having at least one microchannel and a capillary element, the capillary element operably connected to and in fluid communication with the microchannel, the kit comprising: a first multiwell plate having a plurality of enzymes disposed within a first plurality of wells; a second multiwell plate having a plurality of enzyme substrates disposed within a second plurality of wells, each one of the second plurality of wells corresponding to one of the first plurality of wells; a phosphate source disposed within each well of the second plate, the phosphate source to be disposed in each of the well at a predetermined phosphate source concentration; a cofactor disposed within each well of the second plate, the cofactor disposed in each well at a predetermined cofactor concentration; wherein the enzyme within each well of the first plate is selected to react with the enzyme substrate, the phosphate source, and the cofactor in the corresponding well of the second plate when the compound is not present; and an instruction set stored on a computer readable medium, the instruction set comprising instructions for controlling dipping of capillary elements into the first plurality of wells; characterized in that the microfluidic device has a first reservoir at one end of the microchannel and a second reservoir at an opposite terminus of the microchannel, the first reservoir having a depth greater than the depth of the second reservoir, the first reservoir having a larger volume relative to the volume or flow rate of the at least one microchannel such that a sample is flowable into the at least one microchannel of the microfluidic device via the capillary element of the microfluidic device by a hydrostatic pressure differential created by the depth differential between the first reservoir and the second reservoir. a first multiwell plate having a plurality of enzymes disposed within a first plurality of wells; a second multiwell plate having a plurality of enzyme substrates disposed within a second plurality of wells, each one of the second plurality of wells corresponding to one of the first plurality of wells; a phosphate source disposed within each well of the second plate, the phosphate source to be disposed in each of the well at a predetermined phosphate source concentration; a cofactor disposed within each well of the second plate, the cofactor disposed in each well at a predetermined cofactor concentration; wherein the enzyme within each well of the first plate is selected to react with the enzyme substrate, the phosphate source, and the cofactor in the corresponding well of the second plate when the compound is not present; and an instruction set stored on a computer readable medium, the instruction set comprising instructions for controlling dipping of capillary elements into the first plurality of wells; characterized in that the microfluidic device has a first reservoir at one end of the microchannel and a second reservoir at an opposite terminus of the microchannel, the first reservoir having a depth greater than the depth of the second reservoir, the first reservoir having a larger volume relative to the volume or flow rate of the at least one microchannel such that a sample is flowable into the at least one microchannel of the microfluidic device via the capillary element of the microfluidic device by a hydrostatic pressure differential created by the depth differential between the first reservoir and the second reservoir.