glycine decarboxylase complex

グリシン脱炭酸酵素複合体、グリシンデカルボキシラーゼ複合体

WordNet

1. complicated in structure; consisting of interconnected parts; "a complex set of variations based on a simple folk melody"; "a complex mass of diverse laws and customs"
2. a compound described in terms of the central atom to which other atoms are bound or coordinated (同)coordination_compound
3. a conceptual whole made up of complicated and related parts; "the complex of shopping malls, houses, and roads created a new town" (同)composite
4. (psychoanalysis) a combination of emotions and impulses that have been rejected from awareness but still influence a persons behavior
5. any of the enzymes that hydrolize the carboxyl group
6. the simplest amino acid found in proteins and the principal amino acid in sugar cane
7. genus of Asiatic erect or sprawling herbs: soya bean (同)genus Glycine

PrepTutorEJDIC

1. 『いくつかの部分から成る』,複合の,合成の / 『複雑な』,入りくんだ,こみいった(complicated) / 複合体,合成物 / コンプレックス,複合(抑圧されて心に残った複雑なしこり)

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/01/17 21:22:35」(JST)

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Glycine cleavage H-protein
refined structures at 2 angstroms and 2.2 angstroms of the two forms of the h-protein, a lipoamide-containing protein of the glycine decarboxylase
Identifiers
Symbol	GCV_H
Pfam	PF01597
Pfam clan	CL0105
InterPro	IPR002930
SCOP	1htp
SUPERFAMILY	1htp
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Glycine cleavage T-protein, Aminomethyltransferase folate-binding domain
crystal structure of a component of glycine cleavage system: t-protein from pyrococcus horikoshii ot3 at 1.5 a resolution
Identifiers
Symbol	GCV_T
Pfam	PF01571
Pfam clan	CL0289
InterPro	IPR006222
SCOP	1pj5
SUPERFAMILY	1pj5
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Glycine cleavage T-protein C-terminal barrel domain
crystal structure of t-protein of the glycine cleavage system
Identifiers
Symbol	GCV_T_C
Pfam	PF08669
InterPro	IPR013977
SCOP	1pj5
SUPERFAMILY	1pj5
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

The glycine cleavage system (GCS) is also known as the glycine decarboxylase complex or GDC. The system is a series of enzymes that are triggered in response to high concentrations of the amino acid glycine. The same set of enzymes is sometimes referred to as glycine synthase when it runs in the reverse direction to form glycine. The glycine cleavage system is composed of four proteins: the T-protein, P-protein, L-protein, and H-protein. They do not form a stable complex, so it is more appropriate to call it a "system" instead of a "complex". The H-protein is responsible for interacting with the three other proteins and acts as a shuttle for some of the intermediate products in glycine decarboxylation. In both animals and plants the glycine cleavage system is loosely attached to the inner membrane of the mitochondria. Mutations in this enzymatic system are linked with glycine encephalopathy.

Components

Name	EC number	Function
T-protein (GCST or AMT)	EC 2.1.2.10	aminomethyltransferase
P-protein (GLDC)	EC 1.4.4.2	glycine dehydrogenase (decarboxylating) or just glycine dehydrogenase.
L-protein (GCSL or DLD)	EC 1.8.1.4	known by many names, but most commonly dihydrolipoyl dehydrogenase
H-protein (GCSH)		is modified with lipoic acid and interacts with all other components in a cycle of reductive methylamination (catalysed by the P-protein), methylamine transfer (catalysed by the T-protein) and electron transfer (catalysed by the L-protein).

Function

Glycine cleavage

In plants, animals and bacteria the glycine cleavage system catalyzes the following reversible reaction:

Glycine + H₄folate + NAD⁺ ↔ 5,10-methylene-H₄folate + CO₂ + NH₃ + NADH + H⁺

In the enzymatic reaction, H-protein activates the P-protein, which catalyzes the decarboxylation of glycine and attaches the intermediate molecule to the H-protein to be shuttled to the T-protein. The H-protein forms a complex with the T-protein that uses tetrahydrofolate and yields ammonia and 5,10-methylenetetrahydrofolate. After interaction with the T-protein, the H-protein is left with two fully reduced thiol groups in the lipoate group. The glycine protein system is regenerated when the H-protein is oxidized to regenerate the disulfide bond in the active site by interaction with the L-protein, which reduces NAD⁺ to NADH and H⁺.

When coupled to serine hydroxymethyltransferase, the glycine cleavage system overall reaction becomes:

2 glycine + NAD⁺ + H₂O → serine + CO₂ + NH₃ + NADH + H⁺

In humans and most vertebrates, the glycine cleavage system is part of the most prominent glycine and serine catabolism pathway. This is due in large part to the formation 5,10-methylenetetrahydrofolate, which is one of the few C₁ donors in biosynthesis. In this case the methyl group derived from the catabolism of glycine can be transferred to other key molecules such as purines and methionine.

Glycine and serine catabolism in and out of the mitochondria. Inside the mitochondria, the glycine cleavage systems links to the serine hydroxymethyltransferase in a reversible process allowing for flux control in the cell.

This reaction, and by extension the glycine cleavage system, is required for photorespiration in C₃ plants. The glycine cleavage system takes glycine, which is created from an unwanted byproduct of the Calvin cycle, and converts it to serine which can reenter the cycle. The ammonia generated by the glycine cleavage system, is assimilated by the Glutamine synthetase-Glutamine oxoglutarate aminotransferase cycle but costs the cell one ATP and one NADPH. The upside is that one CO₂ is produced for every two O₂ that are mistakenly taken up by the cell, generating some value in an otherwise energy depleting cycle. Together the proteins involved in these reactions comprise about half the proteins in mitochondria from spinach and pea leaves. The glycine cleavage system is constantly present in the leaves of plants, but in small amounts until they are exposed to light. During peak photosynthesis, the concentration of the glycine cleavage system increases ten-fold.

In the anaerobic bacteria, Clostridium acidiurici, the glycine cleavage system runs mostly in the direction of glycine synthesis. While glycine synthesis through the cleavage system is possible due to the reversibility of the overall reaction, it is not readily seen in animals.

Clinical significance

Glycine encephalopathy, also known as non-ketotic hyperglycinemia (NKH), is a primary disorder of the glycine cleavage system, resulting from lowered function of the glycine cleavage system causing increased levels of glycine in body fluids. The disease was first clinically linked to the glycine cleavage system in 1969. Early studied showed high levels of glycine in blood, urine and cerebrospinal fluid. Initial research using carbon labeling showed decreased levels of CO₂ and serine production in the liver, pointing directly to deficiencies glycine cleavage reaction. Further research has shown that deletions and mutations in the 5' region of the P-protein are the major genetic causes of nonketotic hyperglycinemia. . In more rare cases, a missense mutation in the genetic code of the T-protein, causing the histidine in position 42 to be mutated to arginine, was also found to result in nonketotic hypergycinemia. This specific mutation directly affected the active site of the T-protein, causing lowered efficiency of the glycine cleavage system.

See also

• dihydrolipoamide dehydrogenase
• lipoic acid
• glycine encephalopathy

References

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• Baizabal-Carvallo JF1, Jankovic J1.
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Japanese Journal

• Glycine cleavage system: reaction mechanism, physiological significance, and hyperglycinemia

• Kikuchi Goro,Motokawa Yutaro,Yoshida Tadashi [他],HIRAGA Koichi
• Proceedings of the Japan Academy, Series B 84(7), 246-263, 2008
• … The glycine cleavage system catalyzes the following reversible reaction: Glycine + H<SUB>4</SUB>folate + NAD<SUP>+</SUP>⇄5,10-methylene-H<SUB>4</SUB>folate + CO<SUB>2</SUB> …
• NAID 130000093931

• Investigating the Regulation of One-carbon Metabolism in Arabidopsis thaliana

• Li Rong,Moore Maya,King John
• Plant and cell physiology 44(3), 233-241, 2003-03-01
• NAID 80015847694

• The pathogen-inducible nitric oxide synthase (iNOS) is a variant of the P protein of the glycine decarboxylase complex

• CHANDOK M. R.
• Cell 113, 469-482, 2003
• NAID 80015983846

Related Links

• Glycine decarboxylase complex | Online references ...

References for "Glycine decarboxylase complex" im Internet, an Universitäten und in der Literatur... cyclopaedia.net ... Dipeptides and tripeptides serve as important sources of amino acids, nitrogen and carbon for the growth of all ...

• Glycine decarboxylase multienzyme complex. Purification ...

[show abstract] [hide abstract] ABSTRACT: Several thousand plant genes are known to produce multiple transcripts, but the precise function of most of the alternatively encoded proteins is not known. Alternative splicing has been ...

Related Pictures

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★リンクテーブル★

リンク元	「グリシン脱炭酸酵素複合体」「グリシンデカルボキシラーゼ複合体」
拡張検索	「glycine decarboxylase complex H-protein」
関連記事	「complex」「complexed」「decarboxylase」「complexes」

「グリシン脱炭酸酵素複合体」

　　[★]

英

glycine decarboxylase complex

関

グリシンデカルボキシラーゼ複合体

「グリシンデカルボキシラーゼ複合体」

　　[★]

英

glycine decarboxylase complex

関

グリシン脱炭酸酵素複合体

「glycine decarboxylase complex H-protein」

　　[★] (リポ酸を含有するグリシン脱炭酸酵素複合体の構成タンパク質)グリシン脱炭酸酵素複合体Hタンパク質

「complex」

　　[★]

• n.

• 複合体、錯体、複合物、合成物、(心理)コンプレックス

• adj.

• 複雑な、複合の

関

complexes、complicated、composite、conjugate、intricate

　 　 　 　 　

「complexed」

　　[★]

• adj.

• 複合型の、混合型の

関

hybrid、mixed lineage、mixed type、mixed-type

「decarboxylase」

　　[★]

デカルボキシラーゼ、脱炭酸酵素

関

carboxy-lyase

　

「complexes」

　　[★]

• n.

• 複合体

関

complex、composite