數種動物의 膵組織內 Protein Methylases의 活性度 分布에 관한 硏究 = Distribution of Protein Methylases in Pancreatic Tissues of Various Animals

다국어 초록 (Multilingual Abstract)

Post- translational modification of amino acid residue side-chains in protein has come to be a well known biochemical phenomenon. These reactions include methylation, carboxylation, acetylation, phosphorylation, and hydroxylation. One such side-chain modification of protein, protein methylation is being investigated actively with regard to bacterial chemotaxis, cytochrome c, gene regulation, and carnitine biosynthesis. The methylated amino acids occur in nature in highly specialized proteins. These methylated amino acids are formed by reactions catalyzed by protein methylase Ⅰ, Ⅱ and Ⅲ. In recent studies it was reported that protein carboxymethylation is involved in amylase secretion of parotid gland by isoproterenol. It was also suggested that a small part of the total cellular protein carboxymethylation is directly involved in pancreatic enzyme secretion. On the contrary, other authors reported that there is no relationship between protein carboxymethylation and secretion in pancreas and parotid.
In this study we first examined the activities of protein methylase I, II, and III in pancreatic tissues of various animals, such as rat, mouse, guinea pig, rabbit, pig, cow, cat, chicken, and frog.
The following results were obtained;
1. The activities of protein methylases were generally high in pancreatic tissues of cat, pig, and rabbit. Specifically, the activity of protein methylase I was very high in pancreatic tissue of cat, but low in the tissue of rat. Bovine pancreas had been shown to be the richest source for protein methylase Ⅱ, while the activity of protein methylase Ⅲ was relatively high in pancreatic tissue of cat.
2. The activities of protein methylase Ⅰ, Ⅱ, and Ⅲ in pancreatic tissue of chicken were generally high.
3. Interestingly, the activities of protein methylase Ⅰ, Ⅱ, and Ⅲ were not detected in pancreatic tissue of frog which is amphibian.