Identification of N-glycan of alpha-fetoprotein by lectin affinity microarray

Purpose The occurrence of cancer accompanies with changes in glycosylation of related proteins. A simple, rapid and high-throughput manner analyzing the N-glycan moiety is needed in the cancer glycoproteome study. Methods Gel-slide was used as solid support of lectin microarray. We fabricated the lectin microarray with selected lectins to identify the N-glycan compositions of glycoproteins, to determine the individual N-glycan pattern of several glycoproteins and to compare the N-glycan compositions of alpha-fetoproteins (AFPs) from different sources. Results It is feasible to analyze N-glycan pattern of glycoproteins with the lectin affinity microarray. The optimum loading concentration of lectins in this array is 1 mg/ml. The lectin microarray is sensitive, and it can even detect tested glycoprotein less than 1 pg. There is a linear relationship between the fluorescence intensity and the cy3 concentration of glycoprotein at the range from 10 to 1,000 nM. Conclusion The lectin microarray could give a panel of lectin affinity patterns of individual glycoproteins, and it could indicate the minimal differences of N-glycan compositions between AFPs from different sources. The developed lectin affinity microarray may contribute to the research of glycoproteomics associated with cancer and other diseases.