Transamination

Transamination is a chemical reaction that transfers an amino group to a ketoacid to form new amino acids. This pathway is responsible for the deamination of most amino acids. This is one of the major degradation pathways which convert essential amino acids to non-essential amino acids (amino acids that can be synthesized de novo by the organism). Transamination in biochemistry is accomplished by enzymes called transaminases or aminotransferases. α-ketoglutarate acts as the predominant amino-group acceptor and produces glutamate as the new amino acid. Aminoacid + α-ketoglutarate ↔ α-keto acid + glutamate Glutamate's amino group, in turn, is transferred to oxaloacetate in a second transamination reaction yielding aspartate. Glutamate + oxaloacetate ↔ α-ketoglutarate + aspartate Transamination catalyzed by aminotransferase occurs in two stages. In the first step, the α amino group of an amino acid is transferred to the enzyme, producing the corresponding α-keto acid and the aminated enzyme. During the second stage, the amino group is transferred to the keto acid acceptor, forming the amino acid product while regenerating the enzyme. The chirality of an amino acid is determined during transamination. For the reaction to complete, aminotransferases require participation of aldehyde containing coenzyme, pyridoxal-5'-phosphate (PLP), a derivative of Pyridoxine (Vitamin B6). The amino group is accommodated by conversion of this coenzyme to pyridoxamine-5'-phosphate (PMP). PLP is covalently attached to the enzyme via a Schiff Base linkage formed by the condensation of its aldehyde group with the ε-amino group of an enzymatic Lys residue. The Schiff base, which is conjugated to the enzyme's pyridinium ring, is the focus of the coenzyme activity. The product of transamination reactions depend on the availability of α-keto acids. The products usually are either alanine, aspartate or glutamate, since their corresponding alpha-keto acids are produced through metabolism of fuels.

À propos de ce résultat

Cette page est générée automatiquement et peut contenir des informations qui ne sont pas correctes, complètes, à jour ou pertinentes par rapport à votre recherche. Il en va de même pour toutes les autres pages de ce site. Veillez à vérifier les informations auprès des sources officielles de l'EPFL.

Publications associées (6)

Unités associées (1)

Concepts associés (14)

Cours associés (2)

Séances de cours associées (11)

BIO-212: Biological chemistry I

Biochemistry is a key discipline for the Life Sciences. Biological Chemistry I and II are two tightly interconnected courses that aim to describe and understand in molecular terms the processes that m

CH-313: Chemical biology

Closely interfacing with bioengineering and medicine, this course provides foundational concepts in applying small-molecule chemical toolsets to probe the functions of living systems at the mechanisti

Elucidating the role of C-terminal post-translational modifications using protein semisynthesis strategies: α-synuclein phosphorylation at tyrosine 125

Hilal Lashuel, Michel Prudent, Bruno Claude Daniel Fauvet, Mirva Hejjaoui, Filip Vercruysse, Yao Zhang

Despite increasing evidence that supports the role of different post-translational modifications (PTMs) in modulating α-synuclein (α-syn) aggregation and toxicity, relatively little is known about the functional consequences of each modification and whethe ...

2012

Synthesis of calcium sensors for labelling fusion proteins-synthesis of modified prolines using aza naked sugar methodology

Agostina Ruggiu

Synthesis of Modified Prolines using aza naked sugar methodology R and S-prolines are secondary, cyclic, pyrrolidine-based amino acids. Proline demonstrated excellent catalytic activity to promote enantio- and diatereoselective, intra- and intermolecular c ...

EPFL2008

Chiral recognition and supramolecular self-assembly of adsorbed amino acids and dipeptides at the submolecular level

Magalí Alejandra Lingenfelder

This thesis deals with the supramolecular organization of chiral aminoacids and dipeptides on metal surfaces. The emergence of homochirality in biomolecular systems is one of the most intriguing open questions of Nature. The self-assembly and amplification ...

EPFL2008

Transaminase

Une transaminase ou aminotransférase est une enzyme qui catalyse un type de réaction entre un acide aminé et un acide α-cétonique. Enzyme à pyridoxal phosphate de la classe des transférases, elle effectue le transfert d'un groupement -NH2 d'un acide aminé vers un autre, permettant la synthèse de nouveaux acides aminés, non présents dans le milieu. Son coenzyme est la vitamine B6 (phosphorylée, ce qui donnera le pyridoxal phosphate). Cette enzyme possède un complexe de coordinence avec un ion cuivre II (Cu2+).

Cétoacide

Les cétoacides sont des acides organiques portant une fonction acide carboxylique et une fonction cétone. On divise cette famille en sous-familles, en classant les composés par rapport aux positions respectives des deux fonctions. On compte parmi ces sous-familles: les alpha-cétoacides, ou 2-oxoacides, qui comme l'acide pyruvique ou le 2-oxoglutarate ou le 2-oxoisovalérate, ont leur fonction cétone adjacente à leur groupe carboxyle (sur le carbone α).

Acide oxaloacétique

L'acide oxaloacétique, dont la base conjuguée est l'oxaloacétate, est un acide dicarboxylique de formule . Il s'agit d'une substance cristallisable qui apparaît notamment comme intermédiaire du cycle de Krebs, de la néoglucogenèse, du cycle de l'urée, du cycle du glyoxylate, de la biosynthèse des acides gras, et de celle de certains acides aminés.

Expansion du code génétique : outils et applications CH-313: Chemical biology

Explore l'expansion du code génétique grâce à l'incorporation d'acides aminés non naturels et à des applications biotechnologiques comme l'affichage d'ARNm et les techniques SILAC-BONCAT.

Vivant avec le syndrome CHARGE BIO-109: Introduction to life sciences (for IC)

Couvre la vie avec le syndrome CHARGE, les plans de repas, la perte de poids et la gestion de la schizophrénie.

Expansion du code génétique : outils et techniques CH-313: Chemical biology

Explore la traduction de l'ARNm, les bloqueurs translationnels, l'expansion du code génétique et les techniques d'étiquetage des protéines.