Cellular debris were sedimented at 12 000 x g for 20 min at 4°C and supernatant harvested and stored at -80°C for subsequent studies. Quantitation of proteins were performed with allowed proceeding in the dark for 45 min at room temperature. Then, the supernatant was removed and the gel pellets were washed with 200 μL of 25 mM NH4HCO3 and vortexed for 15 min. This protocol was repeated three times and then the gels were dehydrated with 25 mM NH4HCO3 in 50% MeCN. The protocol was repeated twice and the gels were dried completely using Speed Vac. For the digestion, 100 uL of 12.5 ng/μL trypsin in 25mM NH4HCO3