[Cytoplasmic enzyme release into the extracellular medium during the freezing and thawing of leukocytes]

The activity of cytoplasmic enzymes (hexokinase, phosphorylase, glucose-6-phosphate dehydrogenase, lactate dehydrogenase) in the extracellular medium following leucocyte freezing-thawing to -30, -70, -140 or -196 degrees C was studied. The appearance of these enzymes in the freezing medium has been found to be associated with the disruption of cellular elements. The source of lactate dehydrogenase activity in the extracellular medium was shown to be due not only to disrupted leucocytes, but also to cells remained after freezing-thawing. Possible mechanisms of the release of enzyme proteins from leucocytes after freezing-thawing are discussed.