Hi Arpita You can try QUANTI-iT Protein assay kit from Invitrogen.
But still there is nearly 20-50% discrepancy between this method and a Abosorbance at 280. I also faced same problem with a protein, then re-cloned by adding a Trp at the C-terminus. Raj E. Rajakumara Postdoctoral Fellow Strcutural Biology Program Memorial Sloan-Kettering Cancer Center New York-10021 NY 001 212 639 7986 (Lab) 001 917 674 6266 (Mobile) --- On Sat, 9/4/11, Arpit Mishra <ar...@igib.in> wrote: From: Arpit Mishra <ar...@igib.in> Subject: [ccp4bb] how to quantitate protein which dont have ne aromatic residue To: CCP4BB@JISCMAIL.AC.UK Date: Saturday, 9 April, 2011, 3:22 PM hello everybody i am working on the protien which dont have any aromatic residue i do fplc other purification using 220 absorption, but i want to quantitate protein precisely i have tried using BCA nd bradford but both methods quantification is not matching,,so any one is having sum idea how to quantitate it precisely thanks in advance for your valuable suggestion.. Arpit Mishra