PURIFICATION AND COMPLETE AMINO-ACID-SEQUENCE OF NOVEL BETA-2-MICROGLOBULIN

We have previously reported that novel β2-microglobulin (β2m) is a metabolite derived from β2m in ultrafiltrate of patients on long-term hemodialysis (LT-HD) [1]. Chromatofocusing showed the presence of at least two major novel β2m's with isoelectric points of 5.38 and 5.22. In the present study we purified one of major novel β2m's and determined the complete amino acid sequence. We demonstrate herein that the novel β2m has the same sequence as native β2m except for the 17th residue from the N-terminus which was identified as Asp instead of Asn in native β2m, suggesting a possible deamidation during LT-HD. © 1990.