Has serum albumin played key roles in the secondary adaptation of cetacea?

2019 Fiscal Year Final Research Report

• Project/Area Number: 18K19346
• Research Category: Grant-in-Aid for Challenging Research (Exploratory)
• Allocation Type: Multi-year Fund
• Review Section: Medium-sized Section 44:Biology at cellular to organismal levels, and related fields
• Research Institution: Nihon University
• Principal Investigator: SUZUKI Miwa 日本大学, 生物資源科学部, 教授 (70409069)
• Project Period (FY): 2018-06-29 – 2020-03-31
• Keywords: 鯨類 / 海中適応 / アルブミン / 抗酸化作用 / 酸化ストレス

Outline of Final Research Achievements

The structures and antioxidant properties of serum albumin of bottlenose dolphin (DSA) were characterized by comparing with human SA (HSA) in this study. Regarding features of the protein structure, our data demonstrated that (1) Cysteine at the 34 position (Cys34), that is present as free thiol and is the most important residue for antioxidant of SA, is replaced to serine in the most cetacean species including bottlenose dolphin, (2) DSA may show different properties of the secondary structure from HSA, and (c) DSA may have a higher thermal stability than HSA. In addition, for antioxidant property, (4) DSA may possess higher antioxidant effects and stronger thiol activity than HSA. These results suggests that cetaceans may have acquired these characteristics of SA competitive with oxidative stress induced by the consequences of their diving-surfacing behaviors during their evolutionally process.

Free Research Field

動物生理学

Academic Significance and Societal Importance of the Research Achievements

本研究により，血中に最も多く存在する血清アルブミン（SA）について，イルカ型アルブミン（DSA）がヒト型（HSA）よりも強いチオール活性と抗酸化力をもつと結論づけられた．このようなSAの獲得は，潜水・浮上に伴い生じる酸化ストレスに常に晒される鯨類にとって，進化上有利であったと考えられる．この成果は，鯨類の潜水生理に新たな知見を導入するだけに止まらず，彼らの抗酸化力の高さ，ひいては彼らの長寿を支えるメカニズムを追求する上でも役立つと期待される．