Efficient monitoring of enzymatic conjugation reaction by surface-enhanced laser desorption/ionization time of flight mass spectrometry for process optimization.
Efficient analysis of bioconjugation reactions is one the most challenging task for optimizing and eventually achieving the reproducible production of large amount of conjugates. In particular, the complexity of some reaction mixtures precludes the use of most of the existing methods, because of the presence of large amounts of contaminants. As an alternative method, we used surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) for monitoring an in vitro enzymatic transglycosylation of N-acetylgalactosamine (GalNAc) residues to a recombinant mucin protein MUC6. For this reaction, catalyzed by the uridine 5'-diphospho-N-acetylgalactosamine:polypeptide N-acetylgalactosaminyltransferases (ppGalNAc-Ts), we used either a recombinant ppGalNAc-T1 or a mixture of ppGalNAc-Ts contained in MCF7 tumor cell extracts. In the present study, we show that SELDI-TOF MS offers unique advantages over the traditional methodologies. It is a rapid, accurate, sensitive, reproducible, and very convenient analytical method for monitoring the course of a bioconjugation, even in heterogeneous samples such as cell extracts. SELDI-TOF MS proved very useful for optimizing the reaction parameters of the transglycosylation and for achieving the large scale preparation of Tn antigen-glycosylated mucins for antitumor immunotherapy applications.
Unité de Chimie Organique URA CNRS 2128, Institut Pasteur, 25-28 rue du Dr. Roux, 75724 Paris, Cedex 15, France.
Teresa
T
Freire
Jacques
J
D'Alayer
Sylvie
S
Bay
D000116:Acetylgalactosamine / Q000737:chemistry*; D000818:Animals; D002417:Cattle; D045744:Cell Line, Tumor; D006801:Humans; D055272:Mucin-6; D009077:Mucins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
C524734:MUC6 protein, human; D055272:Mucin-6; D009077:Mucins; D011994:Recombinant Proteins; D000116:Acetylgalactosamine