(195c) Protamine Purification by Reverse Micelles ExtractionFfrom Model System to Real System

Protamine, a cationic peptide originated from fish milt (spermatic cells), is used as a carrier for injectable insulin, a heparin antagonist in medical field and as an natural antibacterial ingredient in some food products especially with neutral or weak basic pH value. Although protamine is produced commercially, the purification information is unavailable and the published methods in the literature usually involve expensive chromatographic steps and are time consuming. Carp is the largest group of freshwater in China.

In this paper, the reverse micelles extraction of protamine, firstly in model system then complex real system, was studied. Commercial purified salmon protamine is employed in the investigations about model system, and the crude extract of carp fish protamine is used in the sudies on complex real system. The results showed that the extraction behaviors of protamines from salmon and carp are similar.With AOT/isooctane as extractant, salmon protamine is extracted into the reverse micelles easily while the backward extraction is very difficult which process isopropanol enhance significantly. Similarly, after a full extraction cycle, about 100% antibacterial activity of carp protamine in the crude extract could be recovered,with a corresponding relative specific activity of about 2.5 at the extraction conditions, pH 9.0 for forward extraction, and pH=12, 2 M KCl, 40% isopropanol for backward extraction.