tailieunhanh - Báo cáo khoa học: Mass spectrometric detection of tyrosine sulfation in human pancreatic trypsinogens, but not in tumor-associated trypsinogen

Trypsinogen-1 and -2 are well-characterized enzymes that are expressed in the pancreas and also in several other tissues. Many cancers produce tryp-sinogen isoenzymes that differ from the pancreatic ones with respect to substrate specificity and isoelectric point. | ỊFEBS Journal Mass spectrometric detection of tyrosine sulfation in human pancreatic trypsinogens but not in tumor-associated trypsinogen Outi Itkonen1 Jari Helin2 3 Juhani Saarinen2 3 Nisse Kalkkinen2 Konstantin I. Ivanov4 Ulf-Hakan Stenman1 and Leena Valmu5 1 Department of ClinicalChemistry Helsinki University Central Hospital Finland 2 Institute of Biotechnology University of Helsinki Finland 3 Glykos Finland Ltd Helsinki Finland 4 Molecular and Cancer Biology Program University of Helsinki Finland 5 Finnish Red Cross Blood Service Helsinki Finland Keywords ESI-MS post-translationalmodification tyrosine sulfation pancreatic trypsinogen tumor-associated trypsinogen Correspondence L. Valmu Finnish Red Cross Blood Service Research and Development Kivihaantie 7 FIN-00310 Helsinki Finland Fax 358 9 5801310 Tel 358 9 58011 E-mail Received 19 September 2007 revised 15 November 2007 accepted 20 November 2007 doi Trypsinogen-1 and -2 are well-characterized enzymes that are expressed in the pancreas and also in several other tissues. Many cancers produce trypsinogen isoenzymes that differ from the pancreatic ones with respect to substrate specificity and isoelectric point. These tumor-associated trypsinogens play a pivotal role in cancer progression and metastasis. The differences between these and the pancreatic isoenzymes have been suggested to be caused by post-translational modification either sulfation or phosphorylation of a tyrosine residue. We aimed to elucidate the cause of these differences. We isolated trypsinogens from pancreatic juice and conditioned medium from a colon carcinoma cell line. Intact proteins and tryptic and chymotryptic peptides were characterized by electrospray ionization mass spectrometry. We also used immunoblotting with antibody against phosphotyrosine and N-terminal sequencing. The results show that pancreatic trypsinogen-1 and -2 are sulfated at Tyr154 whereas tumor-associated