Vertebral Epidermal Transamidases

The study investigated the role of transamidases in the epidermis, focusing on the transformation of prekeratin to keratin in hair-follicle-free skin. It was found that lysines in prekeratin could be cyanoethylated, whereas in keratin, some lysines were not available for this process. The presence of transamidases, similar to transglutaminases, was identified in the epidermis of various vertebrates, with a molecular weight between 40,000 and 60,000. These enzymes were stimulated by reducing agents and calcium, and were most active in the upper epidermis. The study used [1,4-3H2]putrescine to trace transamidase activity, finding it localized in the stratum corneum, and noted that [1,4-14C2]putrescine incorporation was inhibited by iodoacetamide. Despite these findings, the exact role of transamidases in epidermal metabolism remained unclear.