The influence of ultra-high vacuum on crystalline enzymes

The exploration of physical conditions in space is closely related to the study of the influence of space factors on biological objects. The study of high vacuum is of particular importance because its effects are as yet imperfectly understood. Micro-organisms are suitable models for these investigations. It has already been found that in reference to high vacuum, micro-organisms may be divided into two groups: resistant and nonresistant forms. Bacterial and actinomycetal spores and conidia of Aspergillus are classified as the resistant forms. Parallel with these, rod-shaped non-sporeforming bacteria, yeasts and conidia of Penicillium, were found to be non-resistant forms. The mechanism of resistance and death of micro-organisms under high vacuum is still not clearly understood. Because of this the investigation employing such important macromolecules as crystalline cytochrome C, catalase, peroxidase and ATP have been carried out. These compounds were exposed to a high vacuum (10(-8)-10(-9) mm Hg) over a period of 72 hours. Then the weighed samples taken from treated specimens and controls were dissolved firstly in a phosphate buffer solution (pH=6.8-7.2) and were then diluted by this buffer up to a concentration of 10(-9) mg ml. The solutions obtained were investigated by the chemiluminescent method. It was found that high vacuum effects gave rise to a slight decrease (up 7%) in enzyme activity in concentrated solutions and to a significant inactivation (up to 30%) in diluted ones.