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# Conversion of protein from kDa to gram/L

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### #1 harry348

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Posted 18 February 2013 - 07:17 AM

I have a protein of 17kDa and i want to convert this to gram/Litre.

### #2 phage434

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Posted 18 February 2013 - 07:39 AM

They are different units, they don't convert. Kilodaltons are grams per mole, not grams per liter. You need to know the molarity of the solution you are trying to make.

### #3 harry348

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Posted 18 February 2013 - 07:45 AM

17kDa  (=17kg/mol) ~7x10-6 gram/liter,

is that the right calculation????

### #4 phage434

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Posted 18 February 2013 - 09:13 AM

NO! There is a (very!) large difference between moles and molar. Moles has units of grams. Molar has units of moles per liter.
17 kD means there are 17 kg per MOLE. You cannot determine how many grams per liter there are without knowing how many liters.
I have no idea where your calculation came from, but you simply have insufficient information to do this calculation.

### #5 HOYAJM

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Posted 18 February 2013 - 11:10 AM

If the sample is pure, you can just do an A280 reading by Nanodrop. This will give you a reading in mg/mL. Then you can convert to g/L. The kD does not mean anything in terms of g/L. The kD is only needed to calculate the MOLARITY.