title: Identification and analysis of o-acetylated sialoglycoproteins.
abstract: 5-N-acetylneuraminic acid, commonly known as sialic acid (Sia), constitutes a family of N- and O-substituted 9-carbon monosaccharides. Frequent modification of O-acetylations at positions C-7, C-8, or C-9 of Sias generates a family of O-acetylated sialic acid (O-AcSia) and plays crucial roles in many cellular events like cell-cell adhesion, proliferation, migration, etc. Therefore, identification and analysis of O-acetylated sialoglycoproteins (O-AcSGPs) are important. In this chapter, we describe several approaches for successful identification of O-AcSGPs. We broadly divide them into two categories, i.e., invasive and noninvasive methods. Several O-AcSias-binding probes are used for this purpose. Detailed methodologies for step-by-step identification using these probes have been discussed. We have also included a few invasive analytical methods for identification and quantitation of O-AcSias. Several indirect methods are also elaborated for such purpose, in which O-acetyl group from sialic acids is initially removed followed by detection of Sias by several approaches. For molecular identification, we have described methods for affinity purification of O-AcSGPs using an O-AcSias-binding lectin as an affinity matrix followed by sequencing using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF-TOF) mass spectroscopy (MS). In spite of special attention, loss of O-acetyl groups due to its sensitivity towards alkaline pH and high temperature along with migration of labile O-acetyl groups from C7-C8-C9 during sample preparation is difficult to avoid. Therefore there is always a risk for underestimation of O-AcSias.
authors: Cancer and Cell Biology Division, Council of Scientific and Industrial Research (CSIR)-Indian Institute of Chemical Biology, Kolkata, India.
authors: Chandan
authors: C
authors: Mandal
authors: Chitra
authors: C
authors: Mandal
mesh_terms: D000107:Acetylation; D000818:Animals; D002846:Chromatography, Affinity / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D004912:Erythrocytes / Q000378:metabolism; D006458:Hemolymph / Q000378:metabolism; D006801:Humans; D037102:Lectins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D019158:N-Acetylneuraminic Acid / Q000032:analysis; D012795:Sialoglycoproteins / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D037102:Lectins; D012795:Sialoglycoproteins; D019158:N-Acetylneuraminic Acid