methylmalonyl-CoA racemase

メチルマロニルCoAラセマーゼ

WordNet

1. the 3rd letter of the Roman alphabet (同)c
2. (music) the keynote of the scale of C major
3. a general-purpose programing language closely associated with the UNIX operating system

PrepTutorEJDIC

1. carbonの化学記号
2. cobaltの化学記号

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/07/03 23:33:21」(JST)

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methylmalonyl CoA epimerase
Ribbon diagram of methylmalonyl-CoA epimerase from Propionibacterium shermanii. From PDB: 1JC5 .
Identifiers
EC number	5.1.99.1
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / EGO
Search PMC articles PubMed articles NCBI proteins

methylmalonyl CoA epimerase
Identifiers
Symbol	MCEE
Entrez	84693
HUGO	16732
OMIM	608419
RefSeq	NM_028626
UniProt	Q96PE7
Other data
EC number	5.1.99.1
Locus	Chr. 2 p13.3

Methylmalonyl CoA epimerase (EC 5.1.99.1, methylmalonyl-CoA racemase, methylmalonyl coenzyme A racemase, DL-methylmalonyl-CoA racemase, 2-methyl-3-oxopropanoyl-CoA 2-epimerase [incorrect]) is an enzyme that converts (S)-methylmalonyl-CoA to the (R) form. This enzyme catalyses the following chemical reaction

(R)-methylmalonyl-CoA (S)-methylmalonyl-CoA

Role in Fatty Acid Catabolism

Methylmalonyl CoA epimerase plays an important role in the catabolism of fatty acids with odd-length carbon chains. In the catabolism of even-chain saturated fatty acids, the β-oxidation pathway breaks down fatty acyl-CoA molecules in repeated sequences of four reactions to yield one acetyl CoA per repeated sequence. This means that, for each round of β-oxidation, the fatty acyl-Co-A is shortened by two carbons. If the fatty acid began with an even number of carbons, this process could break down an entire saturated fatty acid into acetyl-CoA units. If the fatty acid began with an odd number of carbons, however, β-oxidation would break the fatty acyl-CoA down until the three carbon propionyl-CoA is formed. In order to convert this to the metabolically useful succinyl-CoA, three reactions are needed. The propionyl-CoA is first carboxylated to (S)-methylmalonyl-CoA by the enzyme Propionyl-CoA carboxylase. Methylmalonyl CoA epimerase then catalyzes the rearrangement of (S)-methylmalonyl-CoA to the (R) form in a reaction that uses a vitamin B12 cofactor and a resonance-stabilized carbanion intermediate. The (R)-methylmalonyl-CoA is then converted to succinyl-CoA in a reaction catalyzed by methylmalonyl-CoA mutase.

Reaction Mechanism

Acting as a general base, the enzyme abstracts a proton from the β-carbon of (R)-methylmalonyl-CoA. This results in the formation of a carbanion intermediate in which the α-carbon is stabilized by resonance. The enzyme then acts as a general acid to protonate the β-carbon, resulting in the formation of (S)-methylmalonyl-CoA.

References

External links

• methylmalonyl-CoA epimerase at the US National Library of Medicine Medical Subject Headings (MeSH)

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

• 1. ペルオキシソーム病 peroxisomal disorders
• 2. Metabolic myopathies caused by disorders of lipid and purine metabolism
• 3. HELLP症候群 hellp syndrome
• 4. 有機酸血症 organic acidemias
• 5. 妊娠時の急性脂肪肝 acute fatty liver of pregnancy

Japanese Journal

• 動物組織におけるプロピオン酸の代謝(IX)Methylmalonyl-CoA racemase

• 高田
• ビタミン 28(5), 386, 1963-11-25
• NAID 110002864029

Related Links

• Methylmalonyl CoA epimerase - Wikipedia, the free encyclopedia

Methylmalonyl CoA epimerase (EC 5.1.99.1, methylmalonyl-CoA racemase, methylmalonyl coenzyme A racemase, DL-methylmalonyl-CoA racemase, 2- methyl-3-oxopropanoyl-CoA 2-epimerase [incorrect]) is an enzyme that converts  ...

• MetaCyc DL-methylmalonyl-CoA racemase - BioCyc

Synonyms: DL-methylmalonyl-coenzyme A racemase, methylmalonyl-CoA epimerase. Species: Rattus norvegicus ... Subunit composition of DL- methylmalonyl-CoA racemase = [methylmalonyl-CoA racemase subunit]2. Molecular Weight of ...

Related Pictures

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★リンクテーブル★

リンク元	「プロピオン酸」「メチルマロニルCoAラセマーゼ」
関連記事	「C」「racemase」「CoA」「COA」「Co」

「プロピオン酸」

　　[★]

英

propionic acid

同

プロパン酸、プロパン

関

カルボン酸

• http://ja.wikipedia.org/wiki/%E3%83%97%E3%83%AD%E3%83%94%E3%82%AA%E3%83%B3%E9%85%B8
• C3H6O2
• CH3-CH2-COOH

• プロピオン酸（プロピオンさん、propionic acid）は示性式CH₃CH₂COOH、分子量74.08のカルボン酸。IUPAC命名法ではプロパン酸 (propanoic acid) となる。CAS登録番号は79-09-4。

物性

• 単体は融点−21℃、沸点141℃の無色の液体で、不快な臭気を有する。水、エタノール、クロロホルム、エーテルなどに溶けやすい。1-プロパノール、プロピオンアルデヒドの酸化によって得られる。

反芻動物におけるプロピオン酸

• 反芻胃で食物の中のセルロースやヘミセルロースを嫌気発酵して、プロピオン酸などの短鎖脂肪酸を生成している。

ヒト(非反芻動物を含む)におけるプロピオン酸

• 奇数脂肪酸のβ酸化、イソロイシンとコレステロール側鎖の酸化によって得られる。(HBC.169)

代謝

HBC. 169

• プロピオン酸　＋　CoA-SH　＋　ATP　－－(acyl-CoA synthetase + Mg2+)－→　AMP　＋　PPi　＋　プロピオニルCoA
• プロピオニルCoA　＋　CO2　＋　H2O　＋　ATP　－－(propionyl-CoA carboxylase+ビオチン)－→　D-メチルマロニルCoA　＋　ADP　＋　Pi

→プロピオン酸血症

• D-メチルマロニルCoA　－－(methylmalonyl-CoA racemase)－→　L-メチルマロニルCoA
• L-メチルマロニルCoA　－－(methylmalonyl-CoA isomerase/methylmalonyl-CoA mutase+ビタミンB12)－→　サクシニルCoA

→メチルマロン酸尿症

誘導体

• イブプロフェン、ナプロキセン、ロキソプロフェンナトリウムなど、Α炭素に芳香族部位が置換した非ステロイド性抗炎症薬 (NSAIDs) が知られ、「プロピオン酸系」と称される。

臨床関連

• メチルマロン酸尿症 methylmalonic aciduria：
• プロピオン酸血症 propionic acidemia：

「メチルマロニルCoAラセマーゼ」

　　[★]

英

methylmalonyl-CoA racemase

「C」

　　[★]

• 炭素 carbon
• シトシン cytosine
• システイン cysteine
• シチジン
• セルシウス度 摂氏 degrees Celsius degree C
• 産婦人科領域で「子宮外頚 子宮外頚部 exocervix」を表現するための略語

　 　 　 　

「racemase」

　　[★]

ラセマーゼ、ラセミ化酵素

関

epimerase、racemase and epimerase

「CoA」

　　[★]

• 大動脈縮窄症 coactation of the aorta
• 補酵素A coenzyme A

「COA」

　　[★] 補酵素A coenzyme A CoA

「Co」

　　[★] コバルト cobalt