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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


3D structure databases


Protocols and materials databases

Structural Biology KnowledgebaseSearch...

Family and domain databases


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: April 12, 2017
This is version 8 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


  1. Glycosyl hydrolases
    Classification of glycosyl hydrolase families and list of entries

Similar proteinsi

Links to similar proteins from the UniProt Reference Clusters (UniRef) at 100%, 90% and 50% sequence identity:
100%UniRef100 combines identical sequences and sub-fragments with 11 or more residues from any organism into one UniRef entry.
90%UniRef90 is built by clustering UniRef100 sequences that have at least 90% sequence identity to, and 80% overlap with, the longest sequence (a.k.a seed sequence).
50%UniRef50 is built by clustering UniRef90 seed sequences that have at least 50% sequence identity to, and 80% overlap with, the longest sequence in the cluster.