UniProt functional annotation for P49235

UniProt code: P49235.

Organism: Zea mays (Maize).
Taxonomy: Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta; Spermatophyta; Magnoliophyta; Liliopsida; Poales; Poaceae; PACMAD clade; Panicoideae; Andropogoneae; Zea.
 
Function: Is implicated in many functions such as ABA metabolism, hydrolysis of conjugated gibberellins, conversion of storage forms of cytokinins to active forms. Also acts in defense of young plant parts against pests via the production of hydroxamic acids from hydroxamic acid glucosides. Enzymatic activity is highly correlated with plant growth. The preferred substrate is DIMBOA- beta-D-glucoside. Hydrolyzes the chromogenic substrate 6-bromo-2- naphthyl-beta-D-glucoside (6BNGlc) and various artificial aryl beta-glucosides. No activity with cellobiose, arbutin, gentiobiose, linamarin or dhurrin as substrates.
 
Catalytic activity: Hydrolysis of terminal, non-reducing beta-D- glucosyl residues with release of beta-D-glucose.
Catalytic activity: (2R)-4-hydroxy-7-methoxy-3-oxo-3,4-dihydro-2H- 1,4-benzoxazin-2-yl beta-D-glucopyranoside + H(2)O = 2,4- dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H)-one + D-glucose.
Catalytic activity: (2R)-4-hydroxy-3-oxo-3,4-dihydro-2H-1,4- benzoxazin-2-yl beta-D-glucopyranoside + H(2)O = 2,4-dihydroxy-2H- 1,4-benzoxazin-3(4H)-one + D-glucose.
Enzyme regulation: Reversibly inhibited by micromolar concentrations of Hg(2+) or Ag(+), but irreversibly inhibited by alkylation in presence of urea. Competitive inhibition by p- nitrophenyl beta-D-thioglucoside (pNPTGlc), glucotetrazole, and para-hydroxy-S-mandelonitrile beta-glucoside (dhurrin).
Biophysicochemical properties: Kinetic parameters: KM=0.14 mM for 4-methylumbelliferyl beta-D-glucopyranoside (MUG); KM=0.64 mM for p-nitrophenyl beta-D-glucopyranoside (PNPG); KM=0.41 mM for p-nitrophenyl beta-D-glucopyranoside (PNPG) (with recombinant enzyme); KM=98 uM for DIMBOA-beta-D-glucoside; KM=0.251 mM for n-octyl-beta-D-glucopyranoside; KM=0.394 mM for p-nitrophenyl beta-D-xyloside; KM=0.648 mM for p-nitrophenyl beta-D-fucopyranoside; KM=0.674 mM for p-nitrophenyl beta-D-cellobioside; KM=0.769 mM for p-nitrophenyl beta-D-mannopyranoside; KM=1.64 mM for o-nitrophenyl beta-D-glucopyranoside; KM=1.42 mM for o-nitrophenyl beta-D-glucopyranoside (with recombinant enzyme); KM=4.32 mM for p-nitrophenyl beta-D-galactopyranoside; Vmax=225.4 umol/h/ug enzyme with p-nitrophenyl beta-D- glucopyranoside as substrate (with recombinant enzyme); Vmax=282.7 umol/h/ug enzyme with o-nitrophenyl beta-D- glucopyranoside as substrate (with recombinant enzyme); pH dependence: Optimum pH is 5.8; Temperature dependence: Optimum temperature is 50 degrees Celsius. Loses activity when is heated at 55 degrees Celsius;
Subunit: Homo- and heterodimer.
Subcellular location: Plastid, chloroplast.
Tissue specificity: Expressed in all seedling parts. Most abundant in the coleoptile.
Similarity: Belongs to the glycosyl hydrolase 1 family.

Annotations taken from UniProtKB at the EBI.