Solid phase synthesis of the protected 27--42 hexadecapeptide of the heavy chain from myeloma immunoglobulin M603. Elimination of side reactions associated with glycyl-2-oxypropionyl-resin

A fully protected 27--42 hexadecapeptide of the variable region of myeloma immunoglobulin M603 was synthesized on a 2-bromopropionyl-resin by the solid phase method. Side reactions due to cyclization of glycyl-2-oxypropionyl-resin were studied under different reaction conditions. The loss of peptide chains at the dipeptide and tripeptide stages due to diketopeperazine formation was also examined. These side reactions were circumvented by using a combination of fragment and stepwise coupling methods. The synthesized protected peptide was removed from the resin in 85% yield by photolysis, and purified by crystallization and by chromatography on a Sephadex LH-60 column.