ID   LALBA_TRIVU             Reviewed;         140 AA.
AC   Q29145;
DT   15-DEC-1998, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   03-AUG-2022, entry version 78.
DE   RecName: Full=Alpha-lactalbumin;
DE   AltName: Full=Lactose synthase B protein;
DE   Flags: Precursor;
GN   Name=LALBA;
OS   Trichosurus vulpecula (Brush-tailed possum).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC   Metatheria; Diprotodontia; Phalangeridae; Trichosurus.
OX   NCBI_TaxID=9337;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], PARTIAL PROTEIN SEQUENCE, AND MASS
RP   SPECTROMETRY.
RC   TISSUE=Mammary gland;
RX   PubMed=9305795; DOI=10.1016/s0304-4165(97)00033-0;
RA   Piotte C.P., Marshall C.J., Hubbard M.J., Collet C., Grigor M.R.;
RT   "Lysozyme and alpha-lactalbumin from the milk of a marsupial, the common
RT   brush-tailed possum (Trichosurus vulpecula).";
RL   Biochim. Biophys. Acta 1336:235-242(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   -!- MASS SPECTROMETRY: Mass=13985; Method=MALDI;
CC       Evidence={ECO:0000269|PubMed:9305795};
CC   -!- SIMILARITY: Belongs to the glycosyl hydrolase 22 family.
CC       {ECO:0000255|PROSITE-ProRule:PRU00680}.
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DR   EMBL; U34288; AAB97108.1; -; mRNA.
DR   AlphaFoldDB; Q29145; -.
DR   SMR; Q29145; -.
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:0005989; P:lactose biosynthetic process; IEA:UniProtKB-KW.
DR   InterPro; IPR001916; Glyco_hydro_22.
DR   InterPro; IPR019799; Glyco_hydro_22_CS.
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; PR00136; LACTALBUMIN.
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; Lactose biosynthesis;
KW   Metal-binding; Milk protein; Secreted; Signal.
FT   SIGNAL          1..19
FT   CHAIN           20..140
FT                   /note="Alpha-lactalbumin"
FT                   /id="PRO_0000018451"
FT   DOMAIN          20..140
FT                   /note="C-type lysozyme"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00680"
FT   BINDING         98
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250|UniProtKB:P00711"
FT   BINDING         101
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250|UniProtKB:P00711"
FT   BINDING         103
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250|UniProtKB:P00711"
FT   BINDING         106
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250|UniProtKB:P00711"
FT   BINDING         107
FT                   /ligand="Ca(2+)"
FT                   /ligand_id="ChEBI:CHEBI:29108"
FT                   /evidence="ECO:0000250|UniProtKB:P00711"
FT   DISULFID        25..140
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00680"
FT   DISULFID        47..131
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00680"
FT   DISULFID        80..96
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00680"
FT   DISULFID        92..110
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00680"
SQ   SEQUENCE   140 AA;  15957 MW;  AAE8405D043BE6B0 CRC64;
     MMSLLPLLLI GIVLPATQAK DYGKCELNQI LRERGVDKVI SLPELICTMF HSSGFSTETE
     VDNNNHKEYG IFQISSNGWC AEKQEDVERS VCGILCSKLL DDDITDDIVC AKKILQLPER
     LDHWKAHNTF CRENLDQWNC