Frontal Affinity Chromatography Coupled to Mass Spectrometry: An Effective Method for K_dDetermination and Screening of α‐Gal Derivatives Binding to Anti‐Gal Antibodies (IgG)

Abstract

Frontal affinity chromatography with mass spectrometric detection (FAC/MS) was developed as an effective method for rapid determination of K d values for a-Gal derivatives binding to human anti-Gal IgG antibodies. Using this method, K d values for 23 a-Gal compounds were determined for the first time, including an a-Gal terminated N-linked oligosaccharide which mimics a single N-glycoform present on the surface of animal cells. A mixture of eight a-Gal derivatives, a model for an a-Gal compound library, was successfully screened against this anti-Gal IgG using FAC/MS. The analyte breakthrough sequence, indicated by the ion chromatogram, reflected the magnitude of the K d values, confirming its potential application in the screening of new a-Gal derivatives and mimetics. Ten a-Gal derivatives were designed and synthesized chemically or enzymatically. Among the compounds analyzed, trivalent compound 26 demonstrated the strongest binding affinity to anti-Gal IgG with a K d value of 3.1 mM. The a-Gal terminated N-linked oligosaccharide 28 had a K d value of 8.6 mM.

New Amphiphilic Glycopolymers Based on a Polycaprolactone‐maleic anhydride Copolymer Backbone: Characterization by 15N NMR and Application to Colloidal Stabilization of Nanoparticles

“…After chromatographic purification, the expected compound was obtained as a colorless oil (55% yield). R f = 0.47 (ethyl acetate/petroleum ether, 2:1); [ α ] D +3.5 ( c = 1.0, CHCl 3 ); 1 H and 13 C NMR were identical with those reported in the literature 30…”

“…R f ¼ 0.47 (ethyl acetate/petroleum ether, 2:1); [a] D þ3.5 (c ¼ 1.0, CHCl 3 ); 1 H and 13 C NMR were identical with those reported in the literature. [30] HRMS (ESI) m/z Calcd. for C 20 …”

“…Since the reaction of triethyleneglycol monochloride with 6, promoted by boron trifluoride etherate, has already been reported in the literature, [30] the same pathway was then followed for the synthesis of 10 from 6. The yields were of the same order than in the mannose series (see Experimental Part).…”

Variations on the SnCl4 and CF3CO2Ag-promoted glycosidation of sugar acetates: a direct, versatile and apparently simple method with either α or β stereocontrol

“…Similarly, a lower selectivity was observed for the BF 3 ÁEt 2 O-promoted synthesis of 21 (1:5 a:b mixture in 66% yield, entry 19), although a 72% yield was reported for a large-scale preparation of pure b-anomer. 38 Under conditions A, 21b was prepared in an 81% yield on the 5-g scale (entry 18), while the lactose derivative 26b (prepared on 0.4 and 5 g scale using 1.5 equiv of alcohol) was also produced in $80% yield, which exceeded markedly the 43% yield previously published. 39 Benzyl glycolate (entry 10) led to b-D-glucosides 13b 35 and a transesterified minor byproduct 14b, with no isolable amounts of the corresponding a-anomers, known to result from oxidative degradation of isomaltulose.…”

“…: R f = 0 38,. 2:3, v/v;½a 20 MHz, CDCl 3 ): d 7.3 (br s, 5H, H-Ar), 5.24 (t, 1H, J = 9.6 Hz, H3), 5.18 (s, 2H, OCH 2 Ph), 5.09 (t, 1H, J = 9.6 Hz, H4), 5.05 (dd, 1H, J 1,2 = 7.8 Hz, J 2,3 = 9.6 Hz, H2), 4.67 (d, 1H, J 1,2 = 7.8 Hz, H1), 4.33 (s, 2H, OCH 2 C=O), 4.25 (dd, 1H, J 5,6a = 4.6 Hz, J 6a,6b = 12.4 Hz, H6a), 4.12 (dd, 1H, J 5,6b = 2.4 Hz, J 6a,6b = 12.4 Hz, H6b), 3.68 (ddd, 1H, J 4,5 = 9.9 Hz, J 5,6a = 4.6 Hz, J 5,6b = 2.4 Hz, H5), 2.08, 2.03, 2.02, 2.01 (4s, 12H, CH 3 CO); 13 C NMR (75 MHz, CDCl 3 ): d 171.1, 170.6, 170.1, 169.8, 169.4 (5s, 5C, C@O), 135.6, 129.1, 129.0, 128.9 (4s, 6C, phenyl), 100.5 (C1), 72.9 (C3), 72.4 (C5), 71.3 (C2), 68.7 (C4), 67.2 (OCH 2 Ph), 65.4 (OCH 2 C@O), 62.2 (C6), 21.2, 21.1, 21.0, 21.0 (4s, 4C, COCH 3 ); MS (ESI, positive mode) m/z : 519.1 [M+Na] + ; Anal.…”