Purification, resolution, and reconstitution of rat liver branched-chain .ALPHA.-keto acid dehydrogenase complex.

• ONO Kazuo

  Department of Biochemistry, Fukushima Medical College

• HAKOZAKI Masatoshi

  Department of Biochemistry, Fukushima Medical College

• KIMURA Atsushi

  Department of Biochemistry, Fukushima Medical College

• KOCHI Hideo

  Department of Biochemistry, Fukushima Medical College

抄録

Branched-chain α-keto acid dehydrogenase (BCKADH) was solubilized as an enzyme complex from rat liver mitochondria by sonic treatment. Dehydrogenase (E₁) and dihydrolipoyltransacylase (E₂) components of the complex were purified in an associated form and resolved into individual components in the presence of 1M NaCl, while lipoamide dehydrogenase (E₃) component was dissociated from the complex during purification. Analysis by gel electrophoresis in dodecyl sulfate revealed the E₁ comprised two different subunits with apparent molecular weights of 36, 000 and 45, 500, presumably in an equal molar ratio, while E₂ consisted of a single subunit with an apparent molecular weight of 51, 000. The BCKADH complex was reconstituted by combining E₁, E₂, and E₃, and the formation of the complex was confirmed by analysis by sucrose density gradient centrifugation. The reconstituted enzyme complex oxidized not only α-ketoisovalerate (KIV), α-ketoiso-caproate (KIC), and α-keto-β-methylvalerate (KMV), but also pyruvate and α-ketoglutarate. Apparent K_m values were 10-12 μM for the branched-chain α-keto acids, 2.2mM for pyruvate, and 2.5mM for α-ketoglutarate.

収録刊行物

• The Journal of Biochemistry

  The Journal of Biochemistry 101 (1), 19-27, 1987

  The Japanese Biochemical Society

詳細情報

• CRID: 1571135653127100672
• NII論文ID: 130003530153
• ISSN: 0021924X
• Web Site: https://jlc.jst.go.jp/DN/JALC/00171727515?from=CiNii
• 本文言語コード: en
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