MetaCyc Enzyme: α-glucan/maltodextrin phosphorylase

Gene: PF1535 Accession Number: G-12579 (MetaCyc)

Species: Pyrococcus furiosus DSM 3638

The apparent molecular mass was determined by SDS-PAGE. The subunit structure of this enzyme has not been reported, although most phosphorylases exist as homodimers or homotetramers and some thermostable enzymes form trimers, hexamers or octamers [Mizanur08].

This enzyme from the hyperthermophilic archaeon Pyrococcus furiosus DSM 3638 catalyzes the reversible cleavage of α-1,4 linked glucose polymers into α-D-glucopyranose 1-phosphate. However its major function in vivo appears to be phosphorolytic degradation of α-glucans. Recombinant enzyme was expressed in Escherichia coli and characterized. Glucan phosphorylases such as this one have potential industrial applications [Mizanur08].

Molecular Weight of Polypeptide: 97.705 kD (from nucleotide sequence), 98.0 kD (experimental) [Mizanur08 ]

Unification Links: Pride:Q8U0Q0 , Protein Model Portal:Q8U0Q0 , String:186497.PF1535 , UniProt:Q8U0Q0

Relationship Links: CAZy:IN-FAMILY:GT35 , Entrez-Nucleotide:PART-OF:AE009950 , InterPro:IN-FAMILY:IPR000811 , InterPro:IN-FAMILY:IPR011834 , InterPro:IN-FAMILY:IPR024517 , Panther:IN-FAMILY:PTHR11468 , Pfam:IN-FAMILY:PF00343 , Pfam:IN-FAMILY:PF11897 , Prosite:IN-FAMILY:PS00102

Gene-Reaction Schematic: ?

Gene-Reaction Schematic

Created 01-Mar-2011 by Fulcher CA , SRI International

Enzymatic reaction of: maltodextrin phosphorylase

a maltodextrin(n) + phosphate <=> a maltodextrin(n-1) + α-D-glucopyranose 1-phosphate

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.

This reaction is reversible. [Mizanur08]

In Pathways: starch degradation V

An electrospray inoization mass spectrometry (ESI-MS) based enzyme assay was used for the determination of α-D-glucopyranose 1-phosphate. Assay was in the phosphorolytic direction using a glycogen as substrate [Mizanur08].

The enzyme was active in the absence of AMP and was unaffected by ADP or ATP. It did not require divalent cations and was not inhibited by them. It functioned over a broad temperature range [Mizanur08].

In the synthetic (reverse) direction, small oligosaccharides (maltopentaose to maltoheptaose) were the most effective acceptors, with maltose showing highest activity. In the degradative (forward) direction, maltotriose was the smallest and least active substrate (although a previous study had shown maltotetraose to be the smallest substrate [Lee06b]). Activity increased from maltotetraose to maltoheptaose and the enzyme also degraded larger glucose-based polymers, forming α-D-glucopyranose 1-phosphate [Mizanur08].

T(opt): 80 °C [Mizanur08]

pH(opt): 6.5 [Mizanur08]


Lee06b: Lee HS, Shockley KR, Schut GJ, Conners SB, Montero CI, Johnson MR, Chou CJ, Bridger SL, Wigner N, Brehm SD, Jenney FE, Comfort DA, Kelly RM, Adams MW (2006). "Transcriptional and biochemical analysis of starch metabolism in the hyperthermophilic archaeon Pyrococcus furiosus." J Bacteriol 188(6);2115-25. PMID: 16513741

Mizanur08: Mizanur RM, Griffin AK, Pohl NL (2008). "Recombinant production and biochemical characterization of a hyperthermostable alpha-glucan/maltodextrin phosphorylase from Pyrococcus furiosus." Archaea 2(3);169-76. PMID: 19054743

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Please cite the following article in publications resulting from the use of MetaCyc: Caspi et al, Nucleic Acids Research 42:D459-D471 2014
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