Asparagine synthase (glutamine-hydrolysing)

Asparagine synthase (glutamine-hydrolysing) (EC 6.3.5.4, asparagine synthetase (glutamine-hydrolysing), glutamine-dependent asparagine synthetase, asparagine synthetase B, AS, AS-B) is an enzyme with systematic name L-aspartate:L-glutamine amido-ligase (AMP-forming).^[1]^[2]^[3]^[4]^[5]^[6] This enzyme catalyses the following chemical reaction

ATP + L-aspartate + L-glutamine + H₂O

\rightleftharpoons

AMP + diphosphate + L-asparagine + L-glutamate (overall reaction)

(1a) L-glutamine + H₂O

\rightleftharpoons

L-glutamate + NH₃

(1b) ATP + L-aspartate + NH₃

\rightleftharpoons

AMP + diphosphate + L-asparagine

The enzyme from Escherichia coli has two active sites6].

References

↑ Patterson, M.K.; Jr.; Orr, G.R. (1968). "Asparagine biosynthesis by the Novikoff hepatoma. Isolation, purification, property, and mechanism studies of the enzyme system". J. Biol. Chem. 243 (2): 376–380. PMID 4295091.
↑ Boehlein, S.K.; Richards, N.G.; Schuster, S.M. (1994). "Glutamine-dependent nitrogen transfer in Escherichia coli asparagine synthetase B. Searching for the catalytic triad". J. Biol. Chem. 269 (10): 7450–7457. PMID 7907328.
↑ Richards, N.G.; Schuster, S.M. (1998). "Mechanistic issues in asparagine synthetase catalysis". Adv. Enzymol. Relat. Areas Mol. Biol. 72: 145–198. PMID 9559053.
↑ Larsen, T.M.; Boehlein, S.K.; Schuster, S.M.; Richards, N.G.; Thoden, J.B.; Holden, H.M.; Rayment, I. (1999). "Three-dimensional structure of Escherichia coli asparagine synthetase B: a short journey from substrate to product". Biochemistry. 38 (49): 16146–16157. doi:10.1021/bi9915768. PMID 10587437.
↑ Huang, X.; Holden, H.M.; Raushel, F.M. (2001). "Channeling of substrates and intermediates in enzyme-catalyzed reactions". Annu. Rev. Biochem. 70: 149–180. doi:10.1146/annurev.biochem.70.1.149. PMID 11395405.
↑ Tesson, A.R.; Soper, T.S.; Ciustea, M.; Richards, N.G. (2003). "Revisiting the steady state kinetic mechanism of glutamine-dependent asparagine synthetase from Escherichia coli". Arch. Biochem. Biophys. 413 (1): 23–31. doi:10.1016/s0003-9861(03)00118-8. PMID 12706338.

Enzymes: CO CS and CN ligases (EC 6.1-6.3)

6.1: Carbon-Oxygen	Aminoacyl tRNA synthetase Alanine Arginine Asparagine Aspartate Cysteine D-alanine—poly(phosphoribitol) ligase Glutamate Glutamine Glycine Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Proline Serine Threonine Tryptophan Tyrosine Valine

6.2: Carbon-Sulfur	Succinyl coenzyme A synthetase Acetyl—CoA synthetase Long-chain-fatty-acid—CoA ligase

6.3: Carbon-Nitrogen	Glutamine synthetase Ubiquitin ligase Cullin Von Hippel–Lindau tumor suppressor UBE3A Mdm2 Anaphase-promoting complex UBR1 Glutathione synthetase CTP synthetase Adenylosuccinate synthase Argininosuccinate synthase Holocarboxylase synthetase GMP synthase Asparagine synthetase Carbamoyl phosphate synthetase I II Glutamate–cysteine ligase

Enzymes

Activity	Active site Binding site Catalytic triad Oxyanion hole Enzyme promiscuity Catalytically perfect enzyme Coenzyme Cofactor Enzyme catalysis Enzyme kinetics Lineweaver–Burk plot Michaelis–Menten kinetics

Regulation	Allosteric regulation Cooperativity Enzyme inhibitor

Classification	EC number Enzyme superfamily Enzyme family List of enzymes

Types	EC1 Oxidoreductases (list) EC2 Transferases (list) EC3 Hydrolases (list) EC4 Lyases (list) EC5 Isomerases (list) EC6 Ligases (list)

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