[Latent activity of liposomal creatine phosphokinase]

Quantitative regimen for the entrapping of creatine phosphokinase (CPK) under different experimental conditions was investigated for the preparation of liposomes with a high internal protein content. As revealed, introduction of 20% of positively-charged lipid (stearyl amine) into the lipid mixture and subsequent one-minute sonication resulted in maximal levels of latent enzyme activity. Maximal entrapment (6.1%) was yielded when 300 mM glucose solution (pH 7.0) AND 0.5 MG OF PROTEIN PER ML WERE USED. Liposome preparations when washed twice at 205 000 g with physiological saline showed minimal external enzyme activity. During storage of liposomes for 7 days under argon protection the internal protein content has not diminished, nor the external activity has increased.