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-MAY-2023, entry version 93. 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; Bacillota; 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 / RC NRRL 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 / RC NRRL 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 / RC NRRL 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}. CC --------------------------------------------------------------------------- CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms CC Distributed under the Creative Commons Attribution (CC BY 4.0) License CC --------------------------------------------------------------------------- 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 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 CDD; cd03143; A4_beta-galactosidase_middle_domain; 1. DR Gene3D; 3.40.50.880; -; 1. DR Gene3D; 3.20.20.80; Glycosidases; 1. DR Gene3D; 2.60.40.1180; Golgi alpha-mannosidase II; 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; BETA-GALACTOSIDASE GANA; 1. DR PANTHER; PTHR36447:SF1; BETA-GALACTOSIDASE GANA; 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; (Trans)glycosidases; 1. DR SUPFAM; SSF52317; Class I glutamine amidotransferase-like; 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 //