TY - JOUR
T1 - Coupling difficulty following replacement of Tyr with HOTic during synthesis of an analog of an EGF B-loop fragment
AU - Ötvös, F.
AU - Murphy, R. F.
AU - Lovas, Sándor
PY - 1999
Y1 - 1999
N2 - During Fmoc synthesis of an analog, [Abu20,31, HOTic22]hEGF(20- 31), of a fragment, Cys-Met-Tyr-Ile-Glu-Ala-Leu-Asp-Lys-Tyr-Ala-Cys, of the B-loop of human EGF, conductivity measurements showed that increased time was necessary for coupling and complete deprotection of the residues Met21 and Abu20 which followed the HOTic22. Use of different active ester-forming reagents, including HOBt and BOP, did not increase the yield. Use of symmetrical anhydride with extended coupling time increased the yield but did not complete the coupling. It appears that inclusion of HOTic in place of Tyr to introduce conformational constraint to peptide analogs can cause or augment a tendency towards conformations with increasing occlusion of N- terminal amino groups and result in the need for altered coupling strategies for completion of analog synthesis.
AB - During Fmoc synthesis of an analog, [Abu20,31, HOTic22]hEGF(20- 31), of a fragment, Cys-Met-Tyr-Ile-Glu-Ala-Leu-Asp-Lys-Tyr-Ala-Cys, of the B-loop of human EGF, conductivity measurements showed that increased time was necessary for coupling and complete deprotection of the residues Met21 and Abu20 which followed the HOTic22. Use of different active ester-forming reagents, including HOBt and BOP, did not increase the yield. Use of symmetrical anhydride with extended coupling time increased the yield but did not complete the coupling. It appears that inclusion of HOTic in place of Tyr to introduce conformational constraint to peptide analogs can cause or augment a tendency towards conformations with increasing occlusion of N- terminal amino groups and result in the need for altered coupling strategies for completion of analog synthesis.
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U2 - 10.1034/j.1399-3011.1999.00026.x
DO - 10.1034/j.1399-3011.1999.00026.x
M3 - Article
C2 - 10231718
AN - SCOPUS:0032951934
VL - 53
SP - 302
EP - 307
JO - Chemical Biology and Drug Design
JF - Chemical Biology and Drug Design
SN - 1747-0277
IS - 3
ER -