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Lupinus albus (White lupine) (Lupinus termis)
Reviewed-Annotation score: Annotation score: 4 out of 5-Experimental evidence at protein leveli


Has hexosaminidase activity. Active with both p-nitrophenyl-beta-D-N-acetylglucosamine (pNP-GlcNAc) and p-nitrophenyl-beta-D-N-acetylgalactosamine (pNP-GalNAc). Not active toward p-nitrophenyl-beta-D-N,N'-diacetylchitobiose (pNP-(GlcNAc)2) or p-nitrophenyl-beta-D-N,N',N''-triacetylchitobiose (pNP-(GlcNAc)3). Removes terminal GlcNAc and may be involved in storage protein degradation.1 Publication

Catalytic activityi

Hydrolysis of terminal non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides.1 Publication

Enzyme regulationi

Inhibited by AgNO3 at a concentration of 0.1 mM. Strongly inhibited by CdCl2, ZnCl2 and FeCl3 and moderately by CoCl2, CuSO4 and NiCl2 at 10 mM concentration. CaCl2, MgCl2, MnSO4 and KI also have a slight inhibitory effect of 20%-25% at 10 mM concentration. Activated to a small extent by MgCl2 at 0.1 mM concentration but inhibited with increasing concentration. Not affected by carbohydrates such as fucose, galactose and glucose but displays a slight decrease in activity up to 25% with lactose, alpha-mannose and N-acetyl-galactosamine (GalNAc).1 Publication


  1. KM=2.59 mM for pNP-GlcNAc1 Publication
  2. KM=2.94 mM for pNP-GalcNAc1 Publication
  1. Vmax=18.4 µmol/min/mg enzyme with pNP-GlcNAc as substrate1 Publication
  2. Vmax=2.73 µmol/min/mg enzyme with pNP-GalcNAc as substrate1 Publication

pH dependencei

Optimum pH is 5.0 with pNP-GlcNAc and 4.0 with pNP-GalNAc. Half maximal activity observed at pH 3.0 and 6.5 with pNP-GlcNAc and at pH 2.5 and 5.5 with pNP-GalNAc. Retains over 90% of its activity between pH 6.5-8.0 with pNP-GlcNAc, and between pH 6.0-7.5 with pNP-GalNAc.1 Publication

Temperature dependencei

Optimum temperature is 50 degrees Celsius toward pNP-GlcNAc and 60 degrees Celsius toward pNP-GalNAc. Displays activity higher than 50% between 35-70 degrees Celsius. Stable under 30 degrees Celsius.1 Publication

GO - Molecular functioni

GO - Biological processi


Molecular functionGlycosidase, Hydrolase

Names & Taxonomyi

Protein namesi
Recommended name:
Beta-hexosaminidase (EC:
Alternative name(s):
Short name:
OrganismiLupinus albus (White lupine) (Lupinus termis)
Taxonomic identifieri3870 [NCBI]
Taxonomic lineageiEukaryotaViridiplantaeStreptophytaEmbryophytaTracheophytaSpermatophytaMagnoliophytaeudicotyledonsGunneridaePentapetalaerosidsfabidsFabalesFabaceaePapilionoideaeGenisteaeLupinus

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
PeptideiPRO_00004225561 – ›26Beta-hexosaminidaseAdd BLAST›26

Post-translational modificationi

Glycosylated.1 Publication

Keywords - PTMi



Tissue specificityi

Detected in dry seeds and cotyledons.1 Publication

Developmental stagei

Activity levels increase 5-9 days after imbibition in the hypocotyls and within 3-9 days in the roots. Detected in dry seeds but increased levels observed 5 days after seed imbibition.1 Publication


Sequence statusi: Fragment.

B3EWR5-1 [UniParc]FASTAAdd to basket

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        10         20 
Mass (Da):2,980
Last modified:November 13, 2013 - v2

Experimental Info

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Sequence uncertaintyi8E or N1
Non-terminal residuei261

Entry informationi

Entry nameiHEXL_LUPAL
AccessioniPrimary (citable) accession number: B3EWR5
Entry historyiIntegrated into UniProtKB/Swiss-Prot: May 29, 2013
Last sequence update: November 13, 2013
Last modified: September 27, 2017
This is version 9 of the entry and version 2 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programPlant Protein Annotation Program


Keywords - Technical termi

Direct protein sequencing