Osmium tetroxide and ruthenium tetroxide and their reactions with biologically important substances

摘要: Summary Few observations giving precise information about the reactions of osmiumtetroxide with biologically important substances exist in literature. In spite this fact general features such have been recognized. The most reliable is found chemical literature, at least osmium tetroxide double bonds. These data and results our own study are derived from under relatively well known vitro conditions cannot be transferred directly to a cellular system. Nevertheless studies may give some idea possible help interpreting structures seen ultrathin sections fixed material, where deposits only “scattering” constituents. An approximate order reactivity suggested: Sulfhydryl groups havea direct reducing action, which partly account for e.g. peptides, proteins enzymes. Double bonds show same reactivity, an outstanding property tetroxide. Reactions olefinic chains exothermic fast, but esters formed rather liable hydrolyse into diol OsO4·2H2O. ester formation cyclic compounds firmly bound certain bond positions molecule concerned gives stable products. This reaction type interest fats, waxes, lecithin, cerebrosides, vitamins, hormones, gallic acids all other biological having basic sterol structure. With tertiary bases easily forms coordination compounds, turn able accelerate appreciably. Such probably occurs tryptophane. Amino terminal position not salt linked, sulfide sulfur, hydroxyl aldehyde on carbon chain lengths, heterocyclic aromatic juxtaposition intense tetroxide, latter being importance when plant material containing tanning studied. Criegee, workers using his method, showed that large number organic affected by steric conditions. explains cases inertness one another compound both very similar structures. carbohydrates nucleic towards OsO4is striking obtained explanation nonimpregnated areas cytoplasm nucleus tissues. From empirical considerations it suggested protein withosmium roughly dependent tryptophane, cysteine histidine/2 content protein. Some enzymes obviously form exceptions rule. Even though rough impression sites tetroxideand thus vague interpretation can given, no conclusions drawn localisation heterogeneous time, temperature concentration, literature suggest constancy temperature, object size, composition fluid essential get comparable used fixation.