Electrophoresis

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Here I will write about presenting data of electrophoresis and also the calculation. What you have is the picture of the gel. You have to make that picture become informative. These are the information that you have to add to the picture:

1. Make the picture in correct direction.
   
2. Name all the well: well of marker/ladder, purified protein, PCR product, negative control, positive control.
   
3. Name all the marker/ladder size.
4. Point out the line of your expected protein/DNA. By the way.. how do you know your sample contained the expected protein/DNA?

Here's, an example from my lab result 5 years ago... but I just edited about 2 hours ago, I didn't point out the expected protein..

Uhm... where's the negative control?? Not remember..

Now, the calculation... Most of you do the wrong calculation for DNA electrophoresis. Okay, I know you got wrong directions... So, now I tell you the correct one. Calculation of DNA and Protein electrophoresis are the same. You have to make calibration curve of the electrophoresis., Log of molecular size against to Migration distance. It supposed to be linear curve.. if you didn't get the linear one.. that's okay. My friend said it usually happens in lab. practice..

Now, about presenting data again.. remember.. informative data.

Table 1. Protein electrophoresis data

Protein Marker size (kDA)	Migration distance (mm)	Log molecular size
16.6	57	1.220
18.4	47	1.265
25.0	32	1.398
35.0	25	1.544
45.0	17	1.653
66.2	8	1.821
116.0	2	2.064

Then, generate the curve and the linear regression.

Figure 1. Protein Electrophoresis Calibration Curve

Got the linear regression equation --> from computer or calculator.

*It's better if you can operate your calculator to find out the linear regression equation*

Where's the sample? Which line was your expected protein/DNA? Measure its migration distance. Do substitution to the equation, then you will get its molecular size...


Then what should you do with the molecular size?
You've been told what protein it was. Find out from the literature what is the size of that protein.. Then compare your result with it.

What should you conclude?
The identity and the size of the sample...


Simple :D

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