We are studying the role of monofuctional isoform of GART enzyme in purine synthesis. To this end, we analyze the intensity of purine synthesis with the help of heavy glycine by LC/MS in HCLO4 hydrolyzate of Hela cells. Adenine mass peak is identified distinctly at mass spectrum while guanine interfered with noise. We use Zorbax SB-Aq C18 column for mass-spectrometry, Mobile gradient phase - Sol A: 0,1 M NH4Ac (pH 5.0) with formic acid, 10% Methanol; Sol B: methanol. UV (DAD): 260 nm

• MSD: ESI+ & ESI-, Scan

. I will be thankful for suggestion how to decrease the noise and identify the guanine peak. Thanks in advance.