AK4 » Adenylate kinase isoenzyme 4, mitochondrial

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Protein also known as: ATP-AMP transphosphorylase.

Gene name: AK4

Family name: Adenylate kinase

This protein has been shown to exist at protein level

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GENE REF ISO

Function

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Overview

Catalyzes the reversible transfer of the terminal phosphate group between ATP and AMP. May also be active with GTP (By similarity).

CuratedUniProtKB

GO molecular function

Adenylate kinase activitydefinition[GO:0004017]

Evidence 1: Inferred from Direct Assay BHF-UCL

Evidence of an intact N-terminal translocation sequence of human mitochondrial adenylate kinase 4.

Panayiotou C., Solaroli N., Johansson M., Karlsson A.

Int. J. Biochem. Cell Biol. 42, 62-69 (2010) [Full text:10.1016/j.biocel.2009.09.007] [PubMed:19766732]

Adenylate kinases are abundant nucleoside monophosphate kinases, which catalyze the phosphorylation of AMP by using ATP or GTP as phosphate donors. A previously cloned cDNA was named adenylate kinase 4 (AK4) based on its sequence similarity with known AKs but with no confirmed AK enzyme activity. In the present study the AK4 cDNA was expressed in Escherichia coli and the substrate specificity and kinetic properties of the recombinant protein were characterized. The enzyme catalyzed the phosphorylation of AMP, dAMP, CMP and dCMP with ATP or GTP as phosphate donors and AK4 also phosphorylated AMP with UTP as phosphate donor. The kinetic parameters of the enzyme were determined for AMP and dAMP with ATP as phosphate donor and for AMP with GTP as phosphate donor. AK4 showed its highest efficiency when phosphorylating AMP with GTP and a slightly lower efficiency for the phosphorylation of AMP with ATP. Among the three reactions for which kinetics were performed, dAMP was the poorest substrate. The AK4 mitochondrial localization was confirmed by expression of AK4 as a fusion protein with GFP in HeLa cells. The mitochondrial import sequence was shown to be located within the first N-terminal 11 amino acid residues, very close to the ATP-binding region of the enzyme. Import analysis suggested that the mitochondrial import sequence was not cleaved and thus the enzyme retained its activity upon entering the mitochondria. Site directed mutagenesis of amino acids Lys 4 and Arg 7 showed that these two residues were essential for mitochondrial import.

ref

IDABHF-UCL

ATP bindingdefinition[GO:0005524]

IEAUniProtKB KW

GTP bindingdefinition[GO:0005525]

IEAUniProtKB KW

Nucleoside triphosphate adenylate kinase activitydefinition[GO:0046899]

Evidence 1: Inferred from Direct Assay BHF-UCL

Evidence of an intact N-terminal translocation sequence of human mitochondrial adenylate kinase 4.

Panayiotou C., Solaroli N., Johansson M., Karlsson A.

Int. J. Biochem. Cell Biol. 42, 62-69 (2010) [Full text:10.1016/j.biocel.2009.09.007] [PubMed:19766732]

Adenylate kinases are abundant nucleoside monophosphate kinases, which catalyze the phosphorylation of AMP by using ATP or GTP as phosphate donors. A previously cloned cDNA was named adenylate kinase 4 (AK4) based on its sequence similarity with known AKs but with no confirmed AK enzyme activity. In the present study the AK4 cDNA was expressed in Escherichia coli and the substrate specificity and kinetic properties of the recombinant protein were characterized. The enzyme catalyzed the phosphorylation of AMP, dAMP, CMP and dCMP with ATP or GTP as phosphate donors and AK4 also phosphorylated AMP with UTP as phosphate donor. The kinetic parameters of the enzyme were determined for AMP and dAMP with ATP as phosphate donor and for AMP with GTP as phosphate donor. AK4 showed its highest efficiency when phosphorylating AMP with GTP and a slightly lower efficiency for the phosphorylation of AMP with ATP. Among the three reactions for which kinetics were performed, dAMP was the poorest substrate. The AK4 mitochondrial localization was confirmed by expression of AK4 as a fusion protein with GFP in HeLa cells. The mitochondrial import sequence was shown to be located within the first N-terminal 11 amino acid residues, very close to the ATP-binding region of the enzyme. Import analysis suggested that the mitochondrial import sequence was not cleaved and thus the enzyme retained its activity upon entering the mitochondria. Site directed mutagenesis of amino acids Lys 4 and Arg 7 showed that these two residues were essential for mitochondrial import.

ref

IDABHF-UCL

GO biological process

AMP metabolic processdefinition[GO:0046033]

Evidence 1: Inferred from Direct Assay BHF-UCL

Evidence of an intact N-terminal translocation sequence of human mitochondrial adenylate kinase 4.

Panayiotou C., Solaroli N., Johansson M., Karlsson A.

Int. J. Biochem. Cell Biol. 42, 62-69 (2010) [Full text:10.1016/j.biocel.2009.09.007] [PubMed:19766732]

Adenylate kinases are abundant nucleoside monophosphate kinases, which catalyze the phosphorylation of AMP by using ATP or GTP as phosphate donors. A previously cloned cDNA was named adenylate kinase 4 (AK4) based on its sequence similarity with known AKs but with no confirmed AK enzyme activity. In the present study the AK4 cDNA was expressed in Escherichia coli and the substrate specificity and kinetic properties of the recombinant protein were characterized. The enzyme catalyzed the phosphorylation of AMP, dAMP, CMP and dCMP with ATP or GTP as phosphate donors and AK4 also phosphorylated AMP with UTP as phosphate donor. The kinetic parameters of the enzyme were determined for AMP and dAMP with ATP as phosphate donor and for AMP with GTP as phosphate donor. AK4 showed its highest efficiency when phosphorylating AMP with GTP and a slightly lower efficiency for the phosphorylation of AMP with ATP. Among the three reactions for which kinetics were performed, dAMP was the poorest substrate. The AK4 mitochondrial localization was confirmed by expression of AK4 as a fusion protein with GFP in HeLa cells. The mitochondrial import sequence was shown to be located within the first N-terminal 11 amino acid residues, very close to the ATP-binding region of the enzyme. Import analysis suggested that the mitochondrial import sequence was not cleaved and thus the enzyme retained its activity upon entering the mitochondria. Site directed mutagenesis of amino acids Lys 4 and Arg 7 showed that these two residues were essential for mitochondrial import.

ref

IDABHF-UCL

ATP metabolic processdefinition[GO:0046034]

Evidence 1: Inferred from Direct Assay BHF-UCL

Evidence of an intact N-terminal translocation sequence of human mitochondrial adenylate kinase 4.

Panayiotou C., Solaroli N., Johansson M., Karlsson A.

Int. J. Biochem. Cell Biol. 42, 62-69 (2010) [Full text:10.1016/j.biocel.2009.09.007] [PubMed:19766732]

Adenylate kinases are abundant nucleoside monophosphate kinases, which catalyze the phosphorylation of AMP by using ATP or GTP as phosphate donors. A previously cloned cDNA was named adenylate kinase 4 (AK4) based on its sequence similarity with known AKs but with no confirmed AK enzyme activity. In the present study the AK4 cDNA was expressed in Escherichia coli and the substrate specificity and kinetic properties of the recombinant protein were characterized. The enzyme catalyzed the phosphorylation of AMP, dAMP, CMP and dCMP with ATP or GTP as phosphate donors and AK4 also phosphorylated AMP with UTP as phosphate donor. The kinetic parameters of the enzyme were determined for AMP and dAMP with ATP as phosphate donor and for AMP with GTP as phosphate donor. AK4 showed its highest efficiency when phosphorylating AMP with GTP and a slightly lower efficiency for the phosphorylation of AMP with ATP. Among the three reactions for which kinetics were performed, dAMP was the poorest substrate. The AK4 mitochondrial localization was confirmed by expression of AK4 as a fusion protein with GFP in HeLa cells. The mitochondrial import sequence was shown to be located within the first N-terminal 11 amino acid residues, very close to the ATP-binding region of the enzyme. Import analysis suggested that the mitochondrial import sequence was not cleaved and thus the enzyme retained its activity upon entering the mitochondria. Site directed mutagenesis of amino acids Lys 4 and Arg 7 showed that these two residues were essential for mitochondrial import.

ref

IDABHF-UCL

Brain developmentdefinition[GO:0007420] ‹silver

IEAOrtholog Compara

Carbon tetrachloride metabolic processdefinition[GO:0018885] ‹silver

IEAOrtholog Compara

GTP metabolic processdefinition[GO:0046039]

Evidence 1: Inferred from Direct Assay BHF-UCL

Evidence of an intact N-terminal translocation sequence of human mitochondrial adenylate kinase 4.

Panayiotou C., Solaroli N., Johansson M., Karlsson A.

Int. J. Biochem. Cell Biol. 42, 62-69 (2010) [Full text:10.1016/j.biocel.2009.09.007] [PubMed:19766732]

Adenylate kinases are abundant nucleoside monophosphate kinases, which catalyze the phosphorylation of AMP by using ATP or GTP as phosphate donors. A previously cloned cDNA was named adenylate kinase 4 (AK4) based on its sequence similarity with known AKs but with no confirmed AK enzyme activity. In the present study the AK4 cDNA was expressed in Escherichia coli and the substrate specificity and kinetic properties of the recombinant protein were characterized. The enzyme catalyzed the phosphorylation of AMP, dAMP, CMP and dCMP with ATP or GTP as phosphate donors and AK4 also phosphorylated AMP with UTP as phosphate donor. The kinetic parameters of the enzyme were determined for AMP and dAMP with ATP as phosphate donor and for AMP with GTP as phosphate donor. AK4 showed its highest efficiency when phosphorylating AMP with GTP and a slightly lower efficiency for the phosphorylation of AMP with ATP. Among the three reactions for which kinetics were performed, dAMP was the poorest substrate. The AK4 mitochondrial localization was confirmed by expression of AK4 as a fusion protein with GFP in HeLa cells. The mitochondrial import sequence was shown to be located within the first N-terminal 11 amino acid residues, very close to the ATP-binding region of the enzyme. Import analysis suggested that the mitochondrial import sequence was not cleaved and thus the enzyme retained its activity upon entering the mitochondria. Site directed mutagenesis of amino acids Lys 4 and Arg 7 showed that these two residues were essential for mitochondrial import.

ref

IDABHF-UCL

Liver developmentdefinition[GO:0001889] ‹silver

IEAOrtholog Compara

Response to drugdefinition[GO:0042493] ‹silver

IEAOrtholog Compara

Tetracycline metabolic processdefinition[GO:0043643] ‹silver

IEAOrtholog Compara

Enzymatic activity

This protein acts as an enzyme. It is known to catalyze the following reaction

EC 2.7.4.3: ATP + AMP ⇄ 2 ADP.

CuratedUniProtKB

Pathways

According to KEGG, this protein belongs to the following pathways:

Metabolic pathways hsa01100+205

Purine metabolism hsa00230+205

Keywords

Molecular function

Kinase definition [KW-0418]

Transferase definition [KW-0808]

Technical term

Reference proteome definition [KW-1185]

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Function

Keywords

neXtProt