540 Chemie und zugeordnete Wissenschaften
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Hemoproteinoids related to contemporary porphyrin-dependent peroxidases were synthesized under simple conditions. The peroxidative activity of hematin increased by a factor of 50 if the hematin was bound to proteinoids whereas the catalatic activity of hematin decreased rather under the same conditions. The peroxidative activity of hemoproteinoids particularly increased with their lysine content whereas the catalatic activity especially decreased in proteinoids with high phenylalanine content. The isoelectric points of the lysine-rich peroxidic hemoproteinoids were about 8. Their relatively broad pH-activity optimum was about pH 7.0. The molecular weights were a little below 20 000. Hematin content and amino acid composition of the synthetic materials were varied greatly. The substrate specificity appeared as broad as that of biogenous peroxidases, e. g., horseradish peroxidase. Among the many substrates was NADH. The possible importance of the peroxidative oxidation of NADH-type coenzymes by primitive heterotrophic organisms or prebiological systems in an anaerobic environment is discussed.
The formation of aliphatic α-amino acids by X-ray induced carboxylation of simple amines or amination of simple carboxylic acids is not favored over the formation of other amino acids. The new carboxylic and amino groups are more or less distributed statistically over the carbon atoms of the starting material. On radiationchemical formation of aliphatic hydrocarbons over C3, therefore, an increasing amount of unusual amino acids is produced. The results are influenced by various parameters such as temperature, pH, concentration, linear energy transfer and total dosis of radiation applied. Also peptides can be formed radiationchemically. However, the formation of greater molecules by radiationchemical processes under the conditions of a primitive earth seems to have only a low probability. The reaction mechanisms of radiationchemical carboxylation and amination are discussed.