Q9KK62 · CBH_BIFLN

  • Protein
    Bile salt hydrolase/transferase
  • Gene
    bsh
  • Status
    UniProtKB reviewed (Swiss-Prot)
  • Amino acids
  • Protein existence
    Evidence at protein level
  • Annotation score
    5/5

Function

function

Possesses dual functions in bile acid metabolism (By similarity).
Acts as a bile salt hydrolase that catalyzes the deconjugation of glycine- and taurine-linked bile salts, which occurs naturally in the intestines of humans, releasing amino acid residues and deconjugated bile salts (bile acids). Can hydrolyze the amide bond in all six major human conjugated bile salts, namely glycocholate (GCA), glycodeoxycholate (GDCA), glycochenodeoxycholate (GCDCA), taurocholate (TCA), taurodeoxycholate (TDCA) and taurochenodeoxycholate (TCDCA). Shows a slight preference for glycine-conjugated bile acids as substrates (PubMed:10831430, PubMed:16905539).
Also acts as an amine N-acyltransferase that conjugates a wide variety of amino acids to conjugated and non-conjugated bile acids, thus producing bacterial bile acid amidates (BBAAs) - also named microbially conjugated bile acids (MCBAs) - in the gastrointestinal tract. These BBAAs may facilitate communication between the microbiota and host through the activation of human ligand-activated transcription factors (By similarity).
Is totally inactive toward penicillin V (PubMed:16905539).

Catalytic activity

  • glycocholate + H2O = cholate + glycine
    This reaction proceeds in the forward direction.
    EC:3.5.1.24 (UniProtKB | ENZYME | Rhea)
  • glycodeoxycholate + H2O = deoxycholate + glycine
    This reaction proceeds in the forward direction.
  • chenodeoxycholate + glycine = glycochenodeoxycholate + H2O
    This reaction proceeds in the backward direction.
  • cholate + taurine = H2O + taurocholate
    This reaction proceeds in the backward direction.
  • H2O + taurodeoxycholate = deoxycholate + taurine
    This reaction proceeds in the forward direction.
  • H2O + taurochenodeoxycholate = chenodeoxycholate + taurine
    This reaction proceeds in the forward direction.
    EC:3.5.1.74 (UniProtKB | ENZYME | Rhea)
  • an L-alpha-amino acid + cholate = an N-choloyl-L-alpha-amino acid + H2O
    This reaction proceeds in the forward direction.
  • an L-alpha-amino acid + taurocholate = an N-choloyl-L-alpha-amino acid + taurine
    This reaction proceeds in the forward direction.
  • cholate + L-alanine = H2O + L-alanocholate
    This reaction proceeds in the forward direction.
  • L-alanine + taurocholate = L-alanocholate + taurine
    This reaction proceeds in the forward direction.
  • cholate + L-serine = H2O + L-serocholate
    This reaction proceeds in the forward direction.
  • L-serine + taurocholate = L-serocholate + taurine
    This reaction proceeds in the forward direction.
  • cholate + L-histidine = H2O + L-histidocholate
    This reaction proceeds in the forward direction.
  • L-histidine + taurocholate = L-histidocholate + taurine
    This reaction proceeds in the forward direction.

Activity regulation

Hydrolase activity is competitively inhibited by the products cholate (CA) and deoxycholate (DCA), and by phenylacetate and 4-aminophenylacetate. Penicillin V and penicillin G show mixed inhibition (PubMed:16905539).
Strongly inhibited by thiol enzyme inhibitors in vitro (PubMed:10831430).

Kinetics

KM SUBSTRATE pH TEMPERATURE[C] NOTES EVIDENCE
0.16 mMglycocholate5.537
0.28 mMglycodeoxycholate5.537
0.13 mMglycochenodeoxycholate5.537
1.12 mMtaurocholate5.537
0.79 mMtaurodeoxycholate5.537
0.33 mMtaurochenodeoxycholate5.537
0.22 mMglycocholate6.540
0.18 mMglycodeoxycholate6.540
0.28 mMglycochenodeoxycholate6.540
0.32 mMtaurocholate6.540
0.49 mMtaurodeoxycholate6.540
0.42 mMtaurochenodeoxycholate6.540
kcat is 85 sec-1 with glycocholate as substrate. kcat is 76 sec-1 with taurocholate as substrate (at 40 degrees Celsius and pH 6.5).

pH Dependence

Optimum pH is 6 for the hydrolase activity. Highly active in the pH range 5-7. Is stable at pH values from 4 to 8. At pH values above 8 and below 4 the enzyme is rapidly inactivated.

Temperature Dependence

Optimum temperature is 40-45 degrees Celsius for the hydrolase activity. Is stable at temperatures from 4 to 37 degrees Celsius. During 30 minutes of incubation at 40 degrees Celsius, about 20 to 30% of the activity is lost, and at 50 degrees Celsius only 20% of the activity is retained.

Pathway

Lipid metabolism; bile acid biosynthesis.

Features

Showing features for active site, binding site.

TypeIDPosition(s)Description
Active site2Nucleophile; acyl-thioester intermediate
Binding site2deoxycholate (UniProtKB | ChEBI)
Binding site18deoxycholate (UniProtKB | ChEBI)
Binding site82taurine (UniProtKB | ChEBI)

GO annotations

AspectTerm
Cellular Componentpeptidoglycan-based cell wall
Molecular Functionchenodeoxycholoyltaurine hydrolase activity
Molecular Functioncholoylglycine hydrolase activity
Molecular Functiontransferase activity
Biological Processbile acid biosynthetic process

Keywords

Enzyme and pathway databases

Protein family/group databases

Chemistry

Names & Taxonomy

Protein names

  • Recommended name
    Bile salt hydrolase/transferase
  • Short names
    BSH/T
  • Alternative names
    • Bile acid amine N-acyltransferase
      (EC:2.3.1.-
      ) . EC:2.3.1.- (UniProtKB | ENZYME | Rhea)
    • Bile salt hydrolase
      (BSH
      )
    • Chenodeoxycholoyltaurine hydrolase
      (EC:3.5.1.74
      ) . EC:3.5.1.74 (UniProtKB | ENZYME | Rhea)
    • Choloylglycine hydrolase
      (EC:3.5.1.24
      ) . EC:3.5.1.24 (UniProtKB | ENZYME | Rhea)
    • Conjugated bile acid hydrolase
      (EC:3.5.1.-
      ) . EC:3.5.1.- (UniProtKB | ENZYME | Rhea)

Gene names

    • Name
      bsh

Organism names

  • Taxonomic identifier
  • Strain
    • SBT2928
  • Taxonomic lineage
    Bacteria > Actinomycetota > Actinomycetes > Bifidobacteriales > Bifidobacteriaceae > Bifidobacterium

Accessions

  • Primary accession
    Q9KK62

Subcellular Location

Phenotypes & Variants

Features

Showing features for mutagenesis.

TypeIDPosition(s)Description
Mutagenesis2Loss of hydrolase activity.
Mutagenesis3About 2-fold decrease in hydrolase activity, but no change in substrate affinity.

PTM/Processing

Features

Showing features for initiator methionine, chain.

TypeIDPosition(s)Description
Initiator methionine1Removed
ChainPRO_00004503242-317Bile salt hydrolase/transferase

Expression

Induction

Is part of an operon containing at least two genes, bsh and glnE (GlnE is glutamine synthetase adenylyltransferase).

Interaction

Subunit

Homotetramer (PubMed:10831430, PubMed:16905539).
The tetramer consists of a dimer of dimers (PubMed:16905539).

Family & Domains

Sequence similarities

Belongs to the peptidase C59 family.

Phylogenomic databases

Family and domain databases

Sequence

  • Sequence status
    Complete
  • Length
    317
  • Mass (Da)
    35,155
  • Last updated
    2000-10-01 v1
  • Checksum
    178B263FBBA205CC
MCTGVRFSDDEGNTYFGRNLDWSFSYGETILVTPRGYHYDTVFGAGGKAKPNAVIGVGVVMADRPMYFDCANEHGLAIAGLNFPGYASFVHEPVEGTENVATFEFPLWVARNFDSVDEVEETLRNVTLVSQIVPGQQESLLHWFIGDGKRSIVVEQMADGMHVHHDDVDVLTNQPTFDFHMENLRNYMCVSNEMAEPTSWGKASLTAWGAGVGMHGIPGDVSSPSRFVRVAYTNAHYPQQNDEAANVSRLFHTLGSVQMVDGMAKMGDGQFERTLFTSGYSSKTNTYYMNTYDDPAIRSYAMADYDMDSSELISVAR

Keywords

Sequence databases

Nucleotide SequenceProtein SequenceMolecule TypeStatus
AF148138
EMBL· GenBank· DDBJ
AAF67801.1
EMBL· GenBank· DDBJ
Genomic DNA

Similar Proteins

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