UniProt functional annotation for Q9ZEU2



	UniProt functional annotation for Q9ZEU2

UniProt code: Q9ZEU2.

Organism: Neisseria polysaccharea.

Taxonomy: Bacteria; Proteobacteria; Betaproteobacteria; Neisseriales; Neisseriaceae; Neisseria.

Function: Catalyzes the synthesis of alpha-glucan from sucrose. Catalyzes, in addition, sucrose hydrolysis, maltose and maltotriose synthesis by successive transfers of the glucosyl moiety of sucrose onto the released glucose, and finally turanose and trehalulose synthesis, these two sucrose isomers being obtained by glucosyl transfer onto fructose. {ECO:0000269|PubMed:9882648}.

Catalytic activity: Reaction=[(1->4)-alpha-D-glucosyl](n) + sucrose = [(1->4)-alpha-D- glucosyl](n+1) + D-fructose; Xref=Rhea:RHEA:24572, Rhea:RHEA- COMP:9584, Rhea:RHEA-COMP:9587, ChEBI:CHEBI:15444, ChEBI:CHEBI:17992, ChEBI:CHEBI:37721; EC=2.4.1.4; Evidence={ECO:0000269|PubMed:10767427, ECO:0000269|PubMed:10828446};

Activity regulation: Amylosucrase favors hydrolysis at low sucrose concentrations, and polymerization at high sucrose concentrations. Competitively inhibited by fructose.

Biophysicochemical properties: Kinetic parameters: KM=1.9 mM for sucrose (in the sucrose consumption assay, when initial sucrose < 20 mM) {ECO:0000269|PubMed:10767427}; KM=1.7 mM for sucrose (in the sucrose hydrolysis reaction, when initial sucrose < 20 mM) {ECO:0000269|PubMed:10767427}; KM=1.9 mM for sucrose (in the polymerization reaction, when initial sucrose < 20 mM) {ECO:0000269|PubMed:10767427}; KM=50.2 mM for sucrose (in the sucrose consumption assay, when initial sucrose > 20 mM) {ECO:0000269|PubMed:10767427}; KM=38.7 mM for sucrose (in the sucrose hydrolysis reaction, when initial sucrose > 20 mM) {ECO:0000269|PubMed:10767427}; Vmax=470 umol/min/g enzyme for sucrose consumption (when initial sucrose < 20 mM) {ECO:0000269|PubMed:10767427}; Vmax=288 umol/min/g enzyme for sucrose hydrolysis (when initial sucrose < 20 mM) {ECO:0000269|PubMed:10767427}; Vmax=147 umol/min/g enzyme for polymerization reaction (when initial sucrose < 20 mM) {ECO:0000269|PubMed:10767427}; Vmax=1100 umol/min/g enzyme for sucrose consumption (when initial sucrose > 20 mM) {ECO:0000269|PubMed:10767427}; Vmax=472 umol/min/g enzyme for sucrose hydrolysis (when initial sucrose > 20 mM) {ECO:0000269|PubMed:10767427}; Vmax=1620 umol/min/g enzyme for polymerization reaction (when initial sucrose > 20 mM) {ECO:0000269|PubMed:10767427}; Note=This enzyme does not present a classic Michaelis-Menten behavior for sucrose consumption, that could be related to the presence of a second sucrose binding site. Nevertheless, it is possible to model sucrose consumption rate versus sucrose concentration by two different Michaelis-Menten equations whose apparent kinetic constants are given just above.;

Subunit: Monomer. {ECO:0000269|PubMed:11467966, ECO:0000269|PubMed:12364331, ECO:0000269|PubMed:15023061, ECO:0000269|PubMed:9882648}.

Subcellular location: Secreted {ECO:0000269|PubMed:9150231}.

Miscellaneous: Like the recombinant protein expressed in E.coli, the amylosucrase may be secreted in N.polysaccharea without cleavage of a signal sequence.

Similarity: Belongs to the glycosyl hydrolase 13 family. {ECO:0000305}.

Sequence caution: Sequence=Ref.1; Type=Frameshift; Evidence={ECO:0000305};

Annotations taken from UniProtKB at the EBI.


Organism:		Neisseria polysaccharea.
Taxonomy:		Bacteria; Proteobacteria; Betaproteobacteria; Neisseriales; Neisseriaceae; Neisseria.



Function:		Catalyzes the synthesis of alpha-glucan from sucrose. Catalyzes, in addition, sucrose hydrolysis, maltose and maltotriose synthesis by successive transfers of the glucosyl moiety of sucrose onto the released glucose, and finally turanose and trehalulose synthesis, these two sucrose isomers being obtained by glucosyl transfer onto fructose. {ECO:0000269\|PubMed:9882648}.


Catalytic activity:		Reaction=[(1->4)-alpha-D-glucosyl](n) + sucrose = [(1->4)-alpha-D- glucosyl](n+1) + D-fructose; Xref=Rhea:RHEA:24572, Rhea:RHEA- COMP:9584, Rhea:RHEA-COMP:9587, ChEBI:CHEBI:15444, ChEBI:CHEBI:17992, ChEBI:CHEBI:37721; EC=2.4.1.4; Evidence={ECO:0000269\|PubMed:10767427, ECO:0000269\|PubMed:10828446};
Activity regulation:		Amylosucrase favors hydrolysis at low sucrose concentrations, and polymerization at high sucrose concentrations. Competitively inhibited by fructose.
Biophysicochemical properties:		Kinetic parameters: KM=1.9 mM for sucrose (in the sucrose consumption assay, when initial sucrose < 20 mM) {ECO:0000269\|PubMed:10767427}; KM=1.7 mM for sucrose (in the sucrose hydrolysis reaction, when initial sucrose < 20 mM) {ECO:0000269\|PubMed:10767427}; KM=1.9 mM for sucrose (in the polymerization reaction, when initial sucrose < 20 mM) {ECO:0000269\|PubMed:10767427}; KM=50.2 mM for sucrose (in the sucrose consumption assay, when initial sucrose > 20 mM) {ECO:0000269\|PubMed:10767427}; KM=38.7 mM for sucrose (in the sucrose hydrolysis reaction, when initial sucrose > 20 mM) {ECO:0000269\|PubMed:10767427}; Vmax=470 umol/min/g enzyme for sucrose consumption (when initial sucrose < 20 mM) {ECO:0000269\|PubMed:10767427}; Vmax=288 umol/min/g enzyme for sucrose hydrolysis (when initial sucrose < 20 mM) {ECO:0000269\|PubMed:10767427}; Vmax=147 umol/min/g enzyme for polymerization reaction (when initial sucrose < 20 mM) {ECO:0000269\|PubMed:10767427}; Vmax=1100 umol/min/g enzyme for sucrose consumption (when initial sucrose > 20 mM) {ECO:0000269\|PubMed:10767427}; Vmax=472 umol/min/g enzyme for sucrose hydrolysis (when initial sucrose > 20 mM) {ECO:0000269\|PubMed:10767427}; Vmax=1620 umol/min/g enzyme for polymerization reaction (when initial sucrose > 20 mM) {ECO:0000269\|PubMed:10767427}; Note=This enzyme does not present a classic Michaelis-Menten behavior for sucrose consumption, that could be related to the presence of a second sucrose binding site. Nevertheless, it is possible to model sucrose consumption rate versus sucrose concentration by two different Michaelis-Menten equations whose apparent kinetic constants are given just above.;
Subunit:		Monomer. {ECO:0000269\|PubMed:11467966, ECO:0000269\|PubMed:12364331, ECO:0000269\|PubMed:15023061, ECO:0000269\|PubMed:9882648}.
Subcellular location:		Secreted {ECO:0000269\|PubMed:9150231}.
Miscellaneous:		Like the recombinant protein expressed in E.coli, the amylosucrase may be secreted in N.polysaccharea without cleavage of a signal sequence.
Similarity:		Belongs to the glycosyl hydrolase 13 family. {ECO:0000305}.
Sequence caution:		Sequence=Ref.1; Type=Frameshift; Evidence={ECO:0000305};