BGAL_GEOKU
ID BGAL_GEOKU Reviewed; 672 AA.
AC P19668;
DT 01-FEB-1991, integrated into UniProtKB/Swiss-Prot.
DT 01-FEB-1991, sequence version 1.
DT 03-AUG-2022, entry version 89.
DE RecName: Full=Beta-galactosidase bgaB;
DE Short=Beta-gal;
DE EC=3.2.1.23;
DE AltName: Full=Beta-galactosidase I;
DE AltName: Full=Lactase;
GN Name=bgaB;
OS Geobacillus kaustophilus.
OC Bacteria; Firmicutes; Bacilli; Bacillales; Bacillaceae; Geobacillus;
OC Geobacillus thermoleovorans group.
OX NCBI_TaxID=1462;
RN [1]
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA], PROTEIN SEQUENCE OF 1-14, AND
RP BIOPHYSICOCHEMICAL PROPERTIES.
RC STRAIN=ATCC 8005 / DSM 7263 / JCM 20319 / NBRC 102445 / NCIMB 8547 / NRRL
RC NRS-81 / IAM 11001 / BD53;
RX PubMed=3086288; DOI=10.1128/jb.166.3.722-727.1986;
RA Hirata H., Fukazawa T., Negoro S., Okada H.;
RT "Structure of a beta-galactosidase gene of Bacillus stearothermophilus.";
RL J. Bacteriol. 166:722-727(1986).
RN [2]
RP CATALYTIC ACTIVITY.
RC STRAIN=ATCC 8005 / DSM 7263 / JCM 20319 / NBRC 102445 / NCIMB 8547 / NRRL
RC NRS-81 / IAM 11001 / BD53;
RX PubMed=6434528; DOI=10.1128/jb.160.1.9-14.1984;
RA Hirata H., Negoro S., Okada H.;
RT "Molecular basis of isozyme formation of beta-galactosidases in Bacillus
RT stearothermophilus: isolation of two beta-galactosidase genes, bgaA and
RT bgaB.";
RL J. Bacteriol. 160:9-14(1984).
RN [3]
RP FUNCTION, CATALYTIC ACTIVITY, BIOPHYSICOCHEMICAL PROPERTIES, ACTIVITY
RP REGULATION, AND BIOTECHNOLOGY.
RC STRAIN=ATCC 8005 / DSM 7263 / JCM 20319 / NBRC 102445 / NCIMB 8547 / NRRL
RC NRS-81 / IAM 11001 / BD53;
RX PubMed=18420605; DOI=10.3168/jds.2007-617;
RA Chen W., Chen H., Xia Y., Zhao J., Tian F., Zhang H.;
RT "Production, purification, and characterization of a potential thermostable
RT galactosidase for milk lactose hydrolysis from Bacillus
RT stearothermophilus.";
RL J. Dairy Sci. 91:1751-1758(2008).
CC -!- FUNCTION: Hydrolyzes 6-bromo-2-naphthyl-beta-D-galactopyranoside and o-
CC nitrophenyl-beta-D-galactopyranoside (ONPG). Possesses a high level of
CC transgalactosylation activity. Hydrolyzes lactose in milk.
CC {ECO:0000269|PubMed:18420605}.
CC -!- CATALYTIC ACTIVITY:
CC Reaction=Hydrolysis of terminal non-reducing beta-D-galactose residues
CC in beta-D-galactosides.; EC=3.2.1.23;
CC Evidence={ECO:0000269|PubMed:18420605, ECO:0000269|PubMed:6434528};
CC -!- ACTIVITY REGULATION: By divalent metal ions. Fe(2+), Zn(2+), Cu(2+),
CC Pb(2+) and Sn(2+) inhibit 52, 76.6, 85.3, 100 and 100% of the enzyme
CC activity, respectively. Other metal cations and EDTA do not inhibit
CC this enzyme. Thiol reagents 2-mercaptoethanol and dithiothreitol have
CC no effect on the activity. Sulfhydryl group-blocking reagents p-
CC chloromercuribenzoic acid and iodoacetic acid inhibit 86.2 and 74% of
CC the enzyme activity, respectively. {ECO:0000269|PubMed:18420605}.
CC -!- BIOPHYSICOCHEMICAL PROPERTIES:
CC Kinetic parameters:
CC KM=2.96 mM for ONPG (at 55 degrees Celsius and pH 7.0)
CC {ECO:0000269|PubMed:18420605, ECO:0000269|PubMed:3086288};
CC Vmax=6.62 umol/min/mg enzyme with ONPG as substrate (at 55 degrees
CC Celsius and pH 7.0) {ECO:0000269|PubMed:18420605,
CC ECO:0000269|PubMed:3086288};
CC pH dependence:
CC Optimum pH is 7.0. Retains more than 80% of the activity at a pH
CC range of 6.0-7.5. {ECO:0000269|PubMed:18420605,
CC ECO:0000269|PubMed:3086288};
CC Temperature dependence:
CC Optimum temperature for the activity is 70 degrees Celsius using ONPG
CC as substrate. Stable up to 70 degrees Celsius (PubMed:3086288).
CC Retains 80% of the activity at 75 degrees Celsius (PubMed:18420605).
CC Kinetics of thermal inactivation and half-life times at 60, 65 and 70
CC degrees Celsius are 120, 50 and 9 hours, respectively.
CC {ECO:0000269|PubMed:18420605, ECO:0000269|PubMed:3086288};
CC -!- BIOTECHNOLOGY: Has potential for enzyme application in low-lactose milk
CC production during milk pasteurization. {ECO:0000269|PubMed:18420605}.
CC -!- SIMILARITY: Belongs to the glycosyl hydrolase 42 family. {ECO:0000305}.
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DR EMBL; M13466; AAA22262.1; -; Genomic_DNA.
DR PIR; A29836; A29836.
DR AlphaFoldDB; P19668; -.
DR SMR; P19668; -.
DR CAZy; GH42; Glycoside Hydrolase Family 42.
DR PRIDE; P19668; -.
DR GO; GO:0009341; C:beta-galactosidase complex; IEA:InterPro.
DR GO; GO:0004565; F:beta-galactosidase activity; IEA:UniProtKB-EC.
DR GO; GO:0046872; F:metal ion binding; IEA:UniProtKB-KW.
DR GO; GO:0006012; P:galactose metabolic process; IEA:InterPro.
DR Gene3D; 2.60.40.1180; -; 1.
DR Gene3D; 3.40.50.880; -; 1.
DR InterPro; IPR013739; Beta_galactosidase_C.
DR InterPro; IPR013738; Beta_galactosidase_Trimer.
DR InterPro; IPR029062; Class_I_gatase-like.
DR InterPro; IPR003476; Glyco_hydro_42.
DR InterPro; IPR013529; Glyco_hydro_42_N.
DR InterPro; IPR013780; Glyco_hydro_b.
DR InterPro; IPR017853; Glycoside_hydrolase_SF.
DR PANTHER; PTHR36447; PTHR36447; 1.
DR Pfam; PF02449; Glyco_hydro_42; 1.
DR Pfam; PF08533; Glyco_hydro_42C; 1.
DR Pfam; PF08532; Glyco_hydro_42M; 1.
DR PIRSF; PIRSF001084; B-galactosidase; 1.
DR SUPFAM; SSF51445; SSF51445; 1.
DR SUPFAM; SSF52317; SSF52317; 1.
PE 1: Evidence at protein level;
KW Direct protein sequencing; Glycosidase; Hydrolase; Metal-binding; Zinc.
FT CHAIN 1..672
FT /note="Beta-galactosidase bgaB"
FT /id="PRO_0000057691"
FT ACT_SITE 148
FT /note="Proton donor"
FT /evidence="ECO:0000250"
FT ACT_SITE 303
FT /note="Nucleophile"
FT /evidence="ECO:0000250"
FT BINDING 109
FT /ligand="substrate"
FT /evidence="ECO:0000250"
FT BINDING 113
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT /evidence="ECO:0000250"
FT BINDING 147
FT /ligand="substrate"
FT /evidence="ECO:0000250"
FT BINDING 156
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT /evidence="ECO:0000250"
FT BINDING 158
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT /evidence="ECO:0000250"
FT BINDING 161
FT /ligand="Zn(2+)"
FT /ligand_id="ChEBI:CHEBI:29105"
FT /evidence="ECO:0000250"
FT BINDING 311
FT /ligand="substrate"
FT /evidence="ECO:0000250"
FT BINDING 351..354
FT /ligand="substrate"
SQ SEQUENCE 672 AA; 78053 MW; FF611FFBEF68F09A CRC64;
MNVLSSICYG GDYNPEQWPE EIWYEDAKLM QKAGVNLVSL GIFSWSKIEP SDGVFDFEWL
DKVIDILYDH GVYINLGTAT ATTPAWFVKK YPDSLPIDES GVILSFGSRQ HYCPNHPQLI
THIKRLVRAI AERYKNHPAL KMWHVNNEYA CHVSKCFCEN CAVAFRKWLK ERYKTIDELN
ERWGTNFWGQ RYNHWDEINP PRKAPTFINP SQELDYYRFM NDSILKLFLT EKEILREVTP
DIPVSTNFMG SFKPLNYFQW AQHVDIVTWD SYPDPREGLP IQHAMMNDLM RSLRKGQPFI
LMEQVTSHVN WRDINVPKPP GVMRLWSYAT IARGADGIMF FQWRQSRAGA EKFHGAMVPH
FLNENNRIYR EVTQLGQELK KLDCLVGSRI KAEVAIIFDW ENWWAVELSS KPHNKLRYIP
IVEAYYRELY KRNIAVDFVR PSDDLTKYKV VIAPMLYMVK EGEDENLRQF VANGGTLIVS
FFSGIVDEND RVHLGGYPGP LRDILGIFVE EFVPYPETKV NKIYSNDGEY DCTTWADIIR
LEGAEPLATF KGDWYAGLPA VTRNCYGKGE GIYVGTYPDS NYLGRLLEQV FAKHHINPIL
EVAENVEVQQ RETDEWKYLI IINHNDYEVT LSLPEDKIYQ NMIDGKCFRG GELRIQGVDV
AVLREHDEAG KV
