N-glycan structures of an osteopontin from human bone

N-Glycan structures of osteopontin (a bone matrix protein) from human bone (lumbar vertabrate) are reported in detail, Asn-linked glycan portion was r eleased from 100 mu g of osteopontin by digestion with glycoamidase A (from sweet almond), and the reducing ends of the N-glycans were reductively ami nated with 2-aminopyridine. The derivatized N-glycans were separated and st ructurally identified by a multidimensional mapping technique on HPLC colum ns. Two major N-glycan structures were also confirmed by mass spectrometry. The proposed structures are shown below, The result should permit future c omparison with the N-glycan structures of osteopontins obtained from other sources (kidney tissues, macrophages, urinary stones, human milk, etc.). [GRAPHICS] (C) 2000 Academic Press.