Function and metabolism of a histidine-containing dipeptide, carnosine, in mammals

肌肽是一种含组氨酸的二肽，在哺乳动物骨骼肌和脑中以高浓度存在。研究表明，它们具有多种生物学功能，包括抗氧化、pH缓冲和营养活性。最近，我们和其他研究小组已经鉴定了负责肌肽合成和降解的酶，但这些酶的功能仍有待研究。在这项研究中，为了阐明这些酶的功能作用，我们分析了这些酶的酶学特性和细胞分布，特别是集中在肌肽降解酶，肌肽二肽酶II（CN 2）。

Carnosine is a histidine-containing dipeptides present at high concentrations in mammalian skeletal muscles and the brain. It has been proposed that they have a variety of biological functions including anti-oxidant, pH-buffering and nutritional activities. Recently, we and other groups have identified the enzymes responsible for carnosine synthesis and degradation, but the function of these enzymes are still to be investigated. In this study, in order to clarify the functional roles of these enzymes, we have analyzed the enzymatic characteristics and cellular distribution of these enzymes, especially focusing on a carnosine-degrading enzyme, carnosine dipeptidase II (CN2).