to run an IEF gel together with IEF markers 

Hi Radha, there is also chromatofocusing and capillary IEF.

Thank you Massod,

Can you please suggest me some protocols to perform acid titration

Alkaline phosphatase, i sonicate bacterial cells in glycine buffer and then centrifuge it to collect supernatant containing alkaline phosphatase. Bacterium producing alkaline phosphatase was isolated from phosphate mines.

is there any method that is not variant of IEF?

Hi Tomáš, I believe Masood is alluding to the fact that proteins are least soluble at their pI.

If you have a concentrated protein solution, you can vary the pH of the buffer and observe when you see precipitation.

OK, I didn't expect that. So there is IEF and its variations and then the acid-titration. Any other method?

(yeah, I was thinking about the calculation, but I'm not sure that would count)

There is also isoelectric focusing gels. These gels won't have the same resolution as CE.  However the price difference may make up for the resolution depending on what you are trying to do, and the amount of resolution you need. 

@Chris isn't that the same as IEF?