L1, a major granulocyte protein; isolation of high quantities of its subunits

Abstract

L1 is a major granulocyte and monocyte protein with a M, of 36.5 kDa. It is found mainly in the cytosol of these cells. Purified LI is shown, on two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), to contain three subunits. In this study, 6 mol/1 concentration of urea was found to be sufficient for disassembly of the polypeptides, and urea-containing preparative isoelectric focusing gel was used for separation of high quantities of the subunits. The pi of the eluted subunits were 5.8, 6.1 and 7.1. When tested on 2D-PAGE, the isolated subunits were found at their typical locations. Polyclonal rabbit antibodies were produced against the subunits, and the antisera were, on dot-blot, found to react with the different subunits as well as the purified LI.

Key Words:

• calprotectin
• dot-blot
• LI subunits
• preparative isoelectric focusing
• purified LI protein
• two-dimensional electrophoresis