PMID-sentid Pub_year Sent_text comp_official_name comp_offsetprotein_name organism prot_offset 8909796-2 1996 GTPase activating proteins (p120GAP, neurofibromin and GAP1) are negative regulators that stimulate hydrolysis of bound GTP to GDP, and guanine nucleotide exchange factors (Sos and Ras-GRF) are positive regulators that stimulate the exchange of GDP bound to Ras for fresh GTP from the cytosol. Radium 181-184 growth hormone releasing hormone Homo sapiens 185-188