ID   LALBA_TACAC             Reviewed;         126 AA.
AC   P81646;
DT   30-MAY-2000, integrated into UniProtKB/Swiss-Prot.
DT   30-MAY-2000, sequence version 1.
DT   03-AUG-2022, entry version 73.
DE   RecName: Full=Alpha-lactalbumin;
DE   AltName: Full=Lactose synthase B protein;
GN   Name=LALBA;
OS   Tachyglossus aculeatus aculeatus (Southeast Australian short-beaked
OS   echidna).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Monotremata; Tachyglossidae; Tachyglossus.
OX   NCBI_TaxID=49271;
RN   [1]
RP   PROTEIN SEQUENCE.
RC   TISSUE=Milk;
RX   PubMed=9440233; DOI=10.1016/s0305-0491(97)00162-4;
RA   Messer M., Griffiths M., Rismiller P.D., Shaw D.C.;
RT   "Lactose synthesis in a monotreme, the echidna (Tachyglossus aculeatus):
RT   isolation and amino acid sequence of echidna alpha-lactalbumin.";
RL   Comp. Biochem. Physiol. 118B:403-410(1997).
CC   -!- FUNCTION: Regulatory subunit of lactose synthase, changes the substrate
CC       specificity of galactosyltransferase in the mammary gland making
CC       glucose a good acceptor substrate for this enzyme. This enables LS to
CC       synthesize lactose, the major carbohydrate component of milk. In other
CC       tissues, galactosyltransferase transfers galactose onto the N-
CC       acetylglucosamine of the oligosaccharide chains in glycoproteins.
CC   -!- SUBUNIT: Lactose synthase (LS) is a heterodimer of a catalytic
CC       component, beta1,4-galactosyltransferase (beta4Gal-T1) and a regulatory
CC       component, alpha-lactalbumin (LA).
CC   -!- SUBCELLULAR LOCATION: Secreted.
CC   -!- TISSUE SPECIFICITY: Mammary gland specific. Secreted in milk.
CC   -!- SIMILARITY: Belongs to the glycosyl hydrolase 22 family.
CC       {ECO:0000255|PROSITE-ProRule:PRU00680}.
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   AlphaFoldDB; P81646; -.
DR   SMR; P81646; -.
DR   GO; GO:0005576; C:extracellular region; IEA:UniProtKB-SubCell.
DR   GO; GO:0005509; F:calcium ion binding; IEA:InterPro.
DR   GO; GO:0004461; F:lactose synthase activity; IEA:InterPro.
DR   GO; GO:0003796; F:lysozyme activity; IEA:InterPro.
DR   GO; GO:0005989; P:lactose biosynthetic process; IEA:UniProtKB-KW.
DR   InterPro; IPR001916; Glyco_hydro_22.
DR   InterPro; IPR019799; Glyco_hydro_22_CS.
DR   InterPro; IPR000974; Glyco_hydro_22_lys.
DR   InterPro; IPR000545; Lactalbumin.
DR   InterPro; IPR023346; Lysozyme-like_dom_sf.
DR   PANTHER; PTHR11407; PTHR11407; 1.
DR   PANTHER; PTHR11407:SF32; PTHR11407:SF32; 1.
DR   Pfam; PF00062; Lys; 1.
DR   PRINTS; PR00137; LYSOZYME.
DR   PRINTS; PR00135; LYZLACT.
DR   SMART; SM00263; LYZ1; 1.
DR   SUPFAM; SSF53955; SSF53955; 1.
DR   PROSITE; PS00128; GLYCOSYL_HYDROL_F22_1; 1.
DR   PROSITE; PS51348; GLYCOSYL_HYDROL_F22_2; 1.
PE   1: Evidence at protein level;
KW   Calcium; Direct protein sequencing; Disulfide bond; Glycoprotein;
KW   Lactose biosynthesis; Metal-binding; Milk protein; Secreted.
FT   CHAIN           1..126
FT                   /note="Alpha-lactalbumin"
FT                   /id="PRO_0000208842"
FT   DOMAIN          1..126
FT                   /note="C-type lysozyme"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00680"
FT   BINDING         84
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250|UniProtKB:P00711"
FT   BINDING         87
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250|UniProtKB:P00711"
FT   BINDING         89
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250|UniProtKB:P00711"
FT   BINDING         92
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250|UniProtKB:P00711"
FT   BINDING         93
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250|UniProtKB:P00711"
FT   CARBOHYD        47
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000250"
FT   DISULFID        6..126
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00680"
FT   DISULFID        30..117
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00680"
FT   DISULFID        63..82
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00680"
FT   DISULFID        78..96
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00680"
SQ   SEQUENCE   126 AA;  14410 MW;  B76A717D5AD70A04 CRC64;
     KVFEKCELSQ MLKANGLDGF QGITLEEWIC IAFHESGFDS RALNYYNGSS SHGLFQINRQ
     YWCDGQDAKS TEPSVNACQI SCDKLRDDDI EDDIKCVKKI LKESQGITAW EAWQPFCIAD
     LDQWKC