title: Mass spectrometric studies of potent inhibitors of farnesyl protein transferase--detection of pentameric noncovalent complexes.
abstract: Farnesyl protein transferase (FPT) inhibition is an interesting and promising approach to noncytotoxic anticancer therapy. Research in this area has resulted in several orally active compounds that are in clinical trials. Electrospray ionization (ESI) time-of-flight mass spectrometry (TOF-MS) was used for the direct detection of a 95 182 Da pentameric noncovalent complex of alpha/beta subunits of FPT containing Zn, farnesyl pyrophosphate (FPP) and SCH 66336, a compound currently undergoing phase III clinical trials as an anticancer agent. It was noted that the desalting of protein samples was an important factor in the detection of the complex. This study demonstrated that the presence of FPP in the system was necessary for the detection of the FPT-inhibitor complex. No pentameric complex was detected in the spectrum when the experiment was carried out in the absence of the FPP. An indirect approach was also applied to confirm the noncovalent binding of SCH 66336 to FPT by the use of an off-line size exclusion chromatography followed by liquid chromatography-electrospray ionization mass spectrometry (LC-ESI-MS) for the detection of the inhibitor.
authors.affiliation: Department of Spectroscopy, Schering-Plough Research Institute, Kenilworth, New Jersey 07033, USA. urooj.mirza@spcorp.com
authors.forename: Urooj A
authors.initials: UA
authors.lastname: Mirza
authors.forename: Guodong
authors.initials: G
authors.lastname: Chen
authors.forename: Yan-Hui
authors.initials: YH
authors.lastname: Liu
authors.forename: Ronald J
authors.initials: RJ
authors.lastname: Doll
authors.forename: Viyyoor M
authors.initials: VM
authors.lastname: Girijavallabhan
authors.forename: Ashit K
authors.initials: AK
authors.lastname: Ganguly
authors.forename: Birendra N
authors.initials: BN
authors.lastname: Pramanik
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D002850:Chromatography, Gel; D004791:Enzyme Inhibitors / Q000378:metabolism / Q000494:pharmacology*; D013058:Mass Spectrometry; D008970:Molecular Weight; D010880:Piperidines / Q000378:metabolism / Q000494:pharmacology*; D011489:Protein Denaturation; D011725:Pyridines / Q000378:metabolism / Q000494:pharmacology*; D021241:Spectrometry, Mass, Electrospray Ionization; D003986:Dibenzocycloheptenes
chemical_list: D019883:Alkyl and Aryl Transferases; D004791:Enzyme Inhibitors; D010880:Piperidines; D011725:Pyridines; C064911:p21(ras) farnesyl-protein transferase; C115354:lonafarnib; D003986:Dibenzocycloheptenes