Intracellular Release of Recombinant Green Fluorescent Protein (fgp_uv) from Escherichia coli

摘要

The recombinant green fluorescent protein (gfp_uv) was expressed by Escherichia coli DH5-#alpha# transformed with the plasmid pGFPuv. The fgp_uv was selectively permeabilized from the cells in buffer solution (25 mM Tris-HCl, pH 8.0), after freezing (- 70 deg C for 15 h), by four freeze (- 20 deg C)/thaw cycles interlaid by sonication. The average content of releaed gfp_uv (experiment 2) was 7.76, 34.58, 39.38, 12.90, and 5.38%, for the initial freezing (-70 deg C) and the first, second, third and fourth freeze/thaw cycles, respectively. Superfusion on freezing was observed between - 11 deg C and - 14 deg C after which it reached - 20 deg C to 0.83 deg C/min.