Quaternary group produced ions for the duration of ECD fragmentation. The ECD spectra in the investigated peptides are much less difficult in comparison with their CID spectra. The amount of formed fragments is lower because the losses of modest molecules are restricted.Molecules 2021, 26, 6964 Molecules 2021, 26, x FOR PEER REVIEW18 of 23 19 of3dRelative Abundance[MH]22 566.CH3 OCH3 OH3C H3CCHCH3 O O POOH3C H3C O O Computer O O CHO H OO H3C OO H3C H3C OTMPP-CH2CO-Asp-Gly-Arg-Thr-Leu-NH1 533.H3COO H3C H3C O CHCHCHc1 590.c1 705.c1 c2 c3 c4 c1 573.763c1 762.269c1 918.c1 966.1 1019.[M]1 1132.m/z4d [MH]22 544.Relative AbundanceCH3 O1 922.CHO H3CH3C H3C O O PO H O OO1 718.CHcc1 975.c1 874.[M]1 1088.523 1050 m/zH3C H3C O1 533.CH0 700 750 800 850 900 950m/z5d [MH]2Relative Abundance2 552.758 1 533.O H3C OO H3C H3C H3C H3C O OCH3 OCH3 OH OPTMPP-CH2CO-Asp-Gly-Lys-Thr-Leu-NH2 b4 c1 c2 c3 c4 cCHc1 590.221 0OCHc1 705.250c1 762.2721 873.bc1 890.c1 991.[M]1 1104.509 1100 m/z7dRelative Abundance[MH]22 551.754 1 533.O H3C OO H3C H3C H3C H3C O OCH3 OCH3 OH OPTMPP-CH2CO-Asp-Gly-Arg-Ala-Leu-NH2 b2 c1 c2 c3 c4 cCHcO CHc1 590.225 0.0 500b1 688.1 705.c1 762.280c1 918.386c1 989.426[M]1 1102.505 1100 m/zFigure 12. ECD-MS for the ion [MH]2 of compounds 3d, 4d, 5d and 7d. Figure 12. ECD-MS for the ion [MH]2 of compounds 3d, 4d, 5d and 7d.3. Materials and Procedures Components and Strategies All specifics regarding Sorafenib supplier applied reagents and equipment areare presentedSupplemendetails regarding applied reagents and equipment presented in in supplementary details. tary Details.3.1. Synthetic Protocol of QAS and QPS Peptide Conjugates 3.1. Synthetic Protocol of QAS and QPS Peptide Conjugates The model peptides were synthesized manually polypropylene syringe reactors (InThe model peptides were synthesized manually in in polypropylene syringe reactors tavis AG) equipped with polyethylene filters, in accordance with a common Fmoc (Intavis AG) equipped with polyethylene filters, based on a regular Fmoc (9-fluorenylmethoxycarbonyl) strong phase synthesis procedure [38] making use of 30 mg of Rink (9-fluorenylmethoxycarbonyl) solid phase synthesis process [38] utilizing 30 mg of Rink Amide Resin (loading 0.68 mmol/g) for every single synthesis. Coupling was performed working with FmocAmide Resin (loading 0.68 mmol/g) for every synthesis. Coupling was performed utilizing protected amino Fmoc-protected acid (three eq), TBTU (2-(1H-Benzotriazole-1-yl)-1,1,3,3-tetramethylaminium amino acid (3 eq), TBTU tetrafluoroborate) (three eq), and DIPEA (N,N-diisopropylethylamine) (six eq) for 2 eq), and (2-(1H-Benzotriazole-1-yl)-1,1,3,3-tetramethylaminium tetrafluoroborate) (3 h at room temperature. Each and every coupling step was eq) for two at room temperature. Soon after syntheDIPEA (N,N-diisopropylethylamine) (6monitoredhby the Kaiser test [39]. Each coupling sis, was monitored by the Kaiser with ABCO, TEA, or TPP employing protocols published by stepthe peptides were derivatized test [39]. Right after synthesis, the peptides had been derivatized Cydzik et al. TEA, or TPP making use of and Waliczek et al. by respectively. [13], Setner et al. with ABCO, [13], Setner et al. [14],protocols published[19], Cydzik et al. As a way to attachment and Waliczek et al. [19], to the N-terminus, order to attachment [14], tris(two,four,6-trimetoxyphenylo)Ubiquitin Related Proteins Source phosphanerespectively. In we made use of precisely the same protocolMolecules 2021, 26,19 ofas ABCO though applying 5 eq of reagent. Just after the reaction was completed, the resin was washed with DMF (7 1 min), DCM (3 1 min), and MeOH (3 1 min), and dried in vacuo. The final step consi.
