WordNet

a class of transferases that catalyze transamination (that transfer an amino group from an amino acid to another compound) (同)aminotransferase, aminopherase

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/07/30 21:13:22」(JST)

wiki en

Aspartate transaminase from E. coli with Pyridoxal 5' Phosphate cofactor

In biochemistry, a transaminase or an aminotransferase is an enzyme that catalyzes a type of reaction between an amino acid and an α-keto acid. To be specific, this reaction (transamination) involves removing the amino group from the amino acid, leaving behind an α-keto acid, and transferring it to the reactant α-keto acid and converting it into an amino acid. Some transamination activities of the ribosome have been found to be catalyzed by so called ribozymes (RNA enzymes). Examples being the hammerhead ribozyme, the VS ribozyme and the hairpin ribozyme.

The transaminase enzymes are important in the production of various amino acids, and measuring the concentrations of various transaminases in the blood is important in the diagnosing and tracking many diseases. Transaminases require the coenzyme pyridoxal-phosphate, which is converted into pyridoxamine in the first phase of the reaction, when an amino acid is converted into a keto acid. Enzyme-bound pyridoxamine in turn reacts with pyruvate, oxaloacetate, or alpha-ketoglutarate, giving alanine, aspartic acid, or glutamic acid, respectively. Many transamination reactions occur in tissues, catalysed by transaminases specific for a particular amino/keto acid pair. The reactions are readily reversible, the direction being determined by which of the reactants are in excess. The specific enzymes are named from one of the reactant pairs, for example; the reaction between glutamic acid and pyruvic acid to make alpha ketoglutaric acid and alanine is called glutamic-pyruvic transaminase or GPT for short. Tissue transaminase activities can be investigated by incubating a homogenate with various amino/keto aci dpairs. Transamination is demonstrated if the corresponding new amino acid and keto acid are formed, as revealed by paper chromatography. Reversibility is demonstrated by using the complementary keto/amino acid pari as starting reactants. After chromatogram has been taken out of the solvent the chromatogram is then treated with ninhydrin to locate the spots.

Two important transaminase enzymes are AST (SGOT) and ALT (SGPT), the presence of elevated transaminases can be an indicator of liver damage.

Transaminases in amino acid metabolism in animals

Animals must metabolize proteins to amino acids, at the expense of muscle tissue, when blood sugar is low. The preference of liver transaminases for oxaloacetate or alpha-ketoglutarate plays a key role in funneling nitrogen from amino acid metabolism to aspartate and glutamate for conversion to urea for excretion of nitrogen. In similar manner, in muscles the use of pyruvate for transamination gives alanine, which is carried by the bloodstream to the liver (the overall reaction being termed glucose-alanine cycle). Here other transaminases regenerate pyruvate, which provides a valuable precursor for gluconeogenesis. This alanine cycle is analogous to the Cori cycle, which allows anaerobic metabolism by muscles.

References

Ghany, Marc & Hoofnagle, Jay H. (2005). Approach to the Patient With Liver Disease. In Dennis L. Kasper, Anthony S. Fauci, Dan L. Longo, Eugene Braunwald, Stephen L. Hauser, & J. Larry Jameson (Eds.), Harrison's Principles of Internal Medicine (16th Edition), pp. 1814–1815. New York: McGraw-Hill.
Nelson, David L. & Cox, Michael M. (2000). Lehninger Principles of Biochemistry (3rd ed.), pp. 628–631, 634, 828–830. New York: Worth Publishers.

External links

Transaminases 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. 肝酵素および肝機能検査値の異常が認められた患者に対するアプローチ approach to the patient with abnormal liver biochemical and function tests
2. 肝線維症の非侵襲的評価：血清学的検査および画像診断 noninvasive assessment of hepatic fibrosis overview of serologic and radiographic tests
3. 肝細胞障害を検出するための肝臓生化学検査 liver biochemical tests that detect injury to hepatocytes
4. 嚢胞性線維症：肝胆道系疾患 cystic fibrosis hepatobiliary disease
5. 小児における腹部の鈍的外傷の概要 overview of blunt abdominal trauma in children

English Journal

Protective mechanisms of wogonoside against Lipopolysaccharide/D-galactosamine-induced acute liver injury in mice.

Gao YZ1, Zhao LF2, Ma J2, Xue WH2, Zhao H2.
European journal of pharmacology.Eur J Pharmacol.2016 Jun 5;780:8-15. doi: 10.1016/j.ejphar.2016.02.040. Epub 2016 Feb 24.
Wogonoside, a bioactive flavonoid extracted from the root of Scutellaria baicalensis Georgi, has been reported to have anti-inflammatory and antioxidant effects. In this study, we examined the protective effects of wogonoside against lipopolysaccharide (LPS) and D-galactosamine (D-GalN)-induced live
PMID 26921756

Flexible Bayesian survival modeling with semiparametric time-dependent and shape-restricted covariate effects.

Murray TA1, Hobbs BP1, Sargent DJ2, Carlin BP3.
Bayesian analysis.Bayesian Anal.2016 Jun;11(2):381-402. Epub 2015 May 14.
Presently, there are few options with available software to perform a fully Bayesian analysis of time-to-event data wherein the hazard is estimated semi- or non-parametrically. One option is the piecewise exponential model, which requires an often unrealistic assumption that the hazard is piecewise
PMID 27042243

Impact of plasma transaminase levels on the peripheral blood glutamate levels and memory functions in healthy subjects.

Kamada Y1, Hashimoto R2, Yamamori H3, Yasuda Y3, Takehara T4, Fujita Y5, Hashimoto K5, Miyoshi E6.
BBA clinical.BBA Clin.2016 Feb 23;5:101-7. doi: 10.1016/j.bbacli.2016.02.004. eCollection 2016.
BACKGROUND & AIMS: Blood aspartate aminotransferase (AST) and alanine transaminase (ALT) levels are the most frequently reliable biomarkers of liver injury. Although AST and ALT play central roles in glutamate production as transaminases, peripheral blood levels of AST and ALT have been regarded
PMID 27051595

Japanese Journal

〈Case Reports〉Hepatocellular carcinoma accompanied by hypersplenism: five cases of simultaneous hepatectomy and laparoscopic splenectomy

Nakata Yasuyuki,Haji Seiji,Yamasaki Mitsuo,Ishikawa Hajime,Yasuda Takeo,Nakai Takuya,Takeyama Yoshifumi
Acta Medica Kinki University 36(2), 81-86, 2011-12
… Hematological analysis included the white blood cell count (WBC), platelet count (Plt), serum alanine transaminase (ALT), total serum bilirubin (T-Bil), prothrombin time (PT)％, and serum albumin (Alb). …
NAID 120003753066

Stimulating Macrophage Activity in Mice and Humans by Oral Administration of Quillaja Saponin

NAKNUKOOL Supaporn,HORINOUCHI Izumi,HATTA Hajime
Bioscience, biotechnology, and biochemistry 75(10), 1889-1893, 2011-10-23
… Furthermore, the volunteers did not show significant changes in immunoglobulin, transaminase, IL-1α, or TNF-α levels, or in serum albumin concentrations. …
NAID 10029872539

「トランスアミナーゼ」

　　[★] アミノトランスフェラーゼ

同: transaminase

補酵素はビリドキシン(ビタミンB6)
αアミノ基をαケト酸に転移する酵素。αアミノ酸の受容体にはふつうαケトグルタル酸が用いられる(グルタミン酸が生成される)。

「アミノ基転移酵素」

　　[★]

英: aminotransferase、transaminase
関: アミノトランスフェラーゼ、トランスアミナーゼ

「アミノトランスフェラーゼ」

　　[★]

英: aminotransferase
同: アミノ基転移酵素、トランスアミナーゼ transaminase

「gamma-aminobutyrate transaminase」

　　[★]

γアミノ酪酸トランスアミナーゼ

関: 4-aminobutyrate transaminase

「tyrosine transaminase」

　　[★]

チロシントランスアミナーゼ

関: tyrosine aminotransferase

「beta-alanine-pyruvate transaminase」

　　[★]

βアラニンピルビン酸トランスアミナーゼ

「glycine transaminase」

　　[★]

グリシントランスアミナーゼ

リンク元	「トランスアミナーゼ」「アミノ基転移酵素」「アミノトランスフェラーゼ」
拡張検索	「gamma-aminobutyrate transaminase」「tyrosine transaminase」「beta-alanine-pyruvate transaminase」「glycine transaminase」

匿名

検索

案内

案内

transaminase