Glycoproteins in gels

A. M. Taylor, O. Holst, and J. Thomas-Oates, Mass spectrometric profiling of O-linked glycans released directly from glycoproteins in gels using in-gel reductive p-elimination, Proteomics, 6 (2006) 2936-2946. 

Fluorescent derivatives of carbohydrate-binding proteins have been used to detect cell-surface and intracellular glycoconjugates by microscopy and flow cytometry, to localize glycoproteins in gels and on protein blots, to precipitate glycoproteins in solution and to cause agglutination of specific cell types. 

The first cloned sequences of the multi-drug resistance transporter (P-glycoprotein, MDR1, ABCB1) were isolated from multi-resistant cell lines in which the gene was strongly amplified. By in-gel renaturation analysis these... 

The biosynthesis in yeast of two enzymes that are D-mannoproteins has been studied. A membrane-associated isozyme of invertase (EC 3.2.1.26) has been shown to be a precursor of the external invertase.190 Its molecular weight, as determined by SDS-poly(acrylamide) gel electrophoresis, is 50,000, that is, smaller than that of the external invertase, and it correlates well with the presence of only the inner-core sugars of the final form. It is strictly bound to membranes, possibly those of the endoplasmic reticulum, and it can be completely split191 by endo-/3-N-acetylglucosaminidase H (EC 3.2.1.30). The addition of tunicamycin, which specifically inhibits formation of d-GIcNAc-PP-DoI, inhibits synthesis of external invertase, as well as further formation of the membrane-associated form, which completely disappears after addition of the antibiotic.190 In these aspects, the synthesis of this extracellular enzyme follows the pathway for secreted glycoproteins in animal systems. 

S. Kilz, H. Budzikiewicz, and S. Waffenschmidt, In-gel deglycosylation of sodiumdodecyl sulfate polyacrylamide gel electrophoresis-separated glycoproteins for carbohydrate estimation by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, J. Mass Spect-rom., 37 (2002) 331-335. 

Fig. 9. Polysialic-acid-containing glycoproteins in newborn and adult rat tissues. Tissue homogenates of brain (B), liver (L), kidney (K), spleen (S), gluteal muscle (M) and heart (H) were subjected to SDS-polyacrylamide gel electrophoresis and polysialic acid was detected using immunoblotting with a monoclonal antibody to the capsular polysaccharides of Escherichia coli K1 and group B meningococci [49]. (From J. Immunol. 138, June 15, 1987, 4402-4407. Copyright 1987, The Journal of Immunology.)...

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