A second isoform of 3-ketoacyl-CoA thiolase found in Caenorhabditis elegans, which is similar to sterol carrier protein x but lacks the sequence of sterol carrier protein 2

European Journal of Biochemistry 245 巻 2 号 252-259 頁 1997 発行
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タイトル ( eng )
A second isoform of 3-ketoacyl-CoA thiolase found in Caenorhabditis elegans, which is similar to sterol carrier protein x but lacks the sequence of sterol carrier protein 2
作成者
Bun-ya Masanori
Maebuchi Motohiro
Hashimoto Takeshi
Yokota Sadaki
Kamiryo Tatsuyuki
収録物名
European Journal of Biochemistry
245
2
開始ページ 252
終了ページ 259
抄録
We cloned a full-length cDNA of the nematode Caenorhabditis elegans that encodes a 44-kDa protein (P-44, 412 residues) similar to sterol carrier protein x (SCPx). Mammalian SCPx is a bipartite protein: its 404-residue N-terminal and 143-residue C-terminal domains are similar to 3-ketoacyl-CoA thiolase and identical to the precursor of sterol carrier protein 2 (SCP2; also termed non-specific lipid-transfer protein), respectively. P-44 has 56(null)equence identity to the thiolase domain of SCx but lacks the SCP2 sequence. Northern blot analysis revealed only a single mRNA species of 1.4 kb, which agrees well with the length of the cDNA (1371 bp), making it improbable that alternative splicing produces an SCPx-like fusion protein. The sequence similarities of P-44 to conventional thiolases are lesser than that to SCPx. Purified recombinant P-44 cleaved long-chain 3-ketoacyl-CoAs (C8-16) in a thiolytic manner by the ping-pong bi-bi reaction mechanism. The inhibition of P-44 by acetyl-CoA was competitive with CoA and non-competitive with 3-ketooctanoyl-CoA. This pattern of inhibition is shared with SCPx but not with conventional 3-ketoacyl-CoA thiolase, which is inhibited uncompetitively with respect to 3-ketoacyl CoA. From these results, we concluded that nematode P-44 and mammalian SCPx constitute a second isoform of thiolase, which we propose to term type-II 3-ketoacyl-CoA thiolase.
著者キーワード
cDNA cloning
3-ketoacyl-CoA thiolase
sterol carrier protein x
sterol carrier protein 2
Caenorhabditis elegans
NDC分類
生物科学・一般生物学 [ 460 ]
言語
英語
資源タイプ 学術雑誌論文
出版者
Federation of European Biochemical Societies
発行日 1997
権利情報
Copyright (c) 1999 Federation of European Biochemical Societies
出版タイプ Author’s Original(十分な品質であるとして、著者から正式な査読に提出される版)
アクセス権 オープンアクセス
収録物識別子
[ISSN] 0014-2956
[NCID] AA00639541
[PMID] 9151950