Open Access

Klaus Dose, Laila Zaki Mohamed Ahmed

• 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.