User:Matthew R Skorski/Notebook/471 - Exp BioChem/2015/10/06

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The objective of today was to run the Bradford Analysis of Protease Degradations for 1 μM Protinase K.


The instructions for the day can be found here. The protocol is identical to the one used on 9/29/15 except the fibers were spun down at 300 rpm for 10 minutes, not 1500 rpm for 1 minute.

  1. Prepping AuNP Fiber Samples
    1. 7 AuNP fiber samples were spun at 300 RPM for 10 minutes
    2. The supernatant was removed but the fibers were retained
    3. Protinase K tube 4 was mixed with 1 mL of 50 mM Tris and 10 mM CaCl2 pH 8 buffer
      1. Protinase K concentration: (0.0014g)*(1mol/28,900g)*(1/0.001L)= 0.000039946 M Protinase K
      2. Amount of Proteinase K solution needed for 1mL with 1μM concentration: M1*V1 = M2*V2 => (39.446 μM)*(V1) = (1 μM)*(1 mL) => V1 = 23.35 mL
      3. Amount of Buffer solution need to get to 1mL: (1mL total)-(23.35 mL Protinase K solution) = 0.97465 mL buffer
  2. Incubating Samples
    1. 23.65 μL Protinase K and 974.65 μL buffer were mixed in the 7 fiber tubes as well as 7 blank eppendorf tubes
    2. Eppendorf tubes were incubated on a shaker in a 37°C water bath for 10 minutes, 15 minutes, 30 minutes, 45 minutes, 1 hrs, 1.5 hrs, and 2 hrs for one of the fiber tubes and one of the blanks.
  3. Running Samples
    1. Once the time for a sample was up the tube was centrifuged at 300 rpm to collect the remaining fibers
    2. To a plastic cuvette was mixed in 600 uL of pre-mixed Bradford dilution, 750 uL of sample, and 1650 uL of buffer
    3. Samples were run from 400-800 nm on the UV-VIS


The graph below shows the absorbance of the samples as function of the wavelength of incident light when corrected. The six samples were first corrected for by subtracting the absorbance of the superblank of buffer and Bradford reagents. Then the samples were corrected for again by subtracting the results of the first correction by the blanks for their corresponding time periods. Then, the isosbestic point at 535 nm from each samples was subtracted from all the wavelengths of that sample.

The graph below shows the peak for the absorbance at 600 nm. From 0 minutest to 15 minutes the aborbance rises, indicating more protein is free in solution. Then it drops at 30 minutes before spiking again at 45 minutes. After 45 minutes the graph makes a decreasing concave up curve with the bottom of the curve hitting at 90 minutes.

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