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Regulation of branched‐chain amino acid (BCAA) catabolism: factors inactivating branched‐chain alpha‐ketoacid dehydrogenase (BCKDH) kinase (LB428)
Author(s) -
Kondo Yusuke,
Itami Yuya,
Zhen Hongmin,
Kitaura Yasuyuki,
Shimomura Yoshiharu
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.lb428
Subject(s) - catabolism , dephosphorylation , valine , amino acid , phosphatase , leucine , phosphorylation , kinase , isoleucine , branched chain amino acid , biochemistry , mitochondrion , alkaline phosphatase , chemistry , medicine , enzyme
BCAAs (leucine, isoleucine, and valine) are essential amino acids. The BCAA catabolism is regulated by BCKDH complex, which is located at the second step of the catabolic pathway. The BCKDH complex is controlled by a covalent modification. BCKDH kinase (BDK) is responsible for inactivation of the complex by phosphorylation, and BCKDH phosphatase (BDP) is for activation of the complex by dephosphorylation. It has been demonstrated that two forms of BDK exists in rat liver mitochondria: a form bound to BCKDH complex and a free form. Only the bound form is suggested to be in active. The regulation of BCKDH complex has been examined under many physiological conditions and the results suggest that BDK is the primary regulator of BCKDH complex by the mechanism in which the amount of the bound form is inversely correlated with the activity state of the complex. In the present study, we addressed to identify factor(s) inactivating BDK and show here the results suggesting that there are new factors that inactivate BDK in rat liver mitochondria. Grant Funding Source : Sponsored by Ajinomoto Amino Acid Research Program 2012