P00713 (LALBA_CAVPO) Reviewed, UniProtKB/Swiss-Prot

Names and origin

Protein names

Recommended name:
Alpha-lactalbumin

Alternative name(s):
Lactose synthase B protein

Gene names

Name:

LALBA

Organism

Cavia porcellus (Guinea pig) [Reference proteome]

Taxonomic identifier

10141 [NCBI]

Taxonomic lineage

cellular organisms › Eukaryota › Opisthokonta › Metazoa › Eumetazoa › Bilateria › Deuterostomia › Chordata › Craniata › Vertebrata › Gnathostomata › Teleostomi › Euteleostomi › Sarcopterygii › Tetrapoda › Amniota › Mammalia › Theria › Eutheria › Euarchontoglires › Glires › Rodentia › Hystricognathi › Caviidae › Cavia

Protein attributes

Sequence length	142 AA.
Sequence status	Complete.
Sequence processing	The displayed sequence is further processed into a mature form.
Protein existence	Evidence at protein level

General annotation (Comments)

Function	Regulatory subunit of lactose synthase, changes the substrate specificity of galactosyltransferase in the mammary gland making glucose a good acceptor substrate for this enzyme. This enables LS to synthesize lactose, the major carbohydrate component of milk. In other tissues, galactosyltransferase transfers galactose onto the N-acetylglucosamine of the oligosaccharide chains in glycoproteins.
Subunit structure	Lactose synthase (LS) is a heterodimer of a catalytic component, beta1,4-galactosyltransferase (beta4Gal-T1) and a regulatory component, alpha-lactalbumin (LA).
Subcellular location	Secreted.
Tissue specificity	Mammary gland specific. Secreted in milk.
Sequence similarities	Belongs to the glycosyl hydrolase 22 family.

Ontologies

Keywords
Biological process	Lactose biosynthesis
Cellular component	Secreted
Domain	Signal
Ligand	Calcium Metal-binding
Molecular function	Milk protein
PTM	Disulfide bond
Technical term	3D-structure Complete proteome Direct protein sequencing Reference proteome
Gene Ontology (GO)
Biological_process	lactose biosynthetic process Inferred from electronic annotation. Source: UniProtKB-KW
Cellular_component	extracellular region Inferred from electronic annotation. Source: UniProtKB-SubCell
Molecular_function	calcium ion binding Inferred from electronic annotation. Source: InterPro lactose synthase activity Inferred from electronic annotation. Source: InterPro
Complete GO annotation...

Sequence annotation (Features)

Feature key

Position(s)

Length

Description

Graphical view

Feature identifier

Molecule processing

Signal peptide

1 – 19

19

Ref.3

Chain

20 – 142

123

Alpha-lactalbumin

PRO_0000018443

Regions

Calcium binding

97 – 108

12

Amino acid modifications

Disulfide bond

25 ↔ 139

Disulfide bond

47 ↔ 130

Disulfide bond

80 ↔ 96

Disulfide bond

92 ↔ 110

Experimental info

Sequence conflict

81

1

E → D in AAA60337. Ref.2

Sequence conflict

124

1

L → F in AAA60337. Ref.2

Secondary structure

1

.

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142

Helix Strand Turn

Details...

Helix

24 – 30

7

Turn

31 – 36

6

Helix

37 – 39

3

Helix

42 – 53

12

Beta strand

60 – 63

4

Beta strand

66 – 69

4

Turn

70 – 73

4

Turn

76 – 79

4

Beta strand

83 – 85

3

Helix

96 – 99

4

Beta strand

100 – 102

3

Helix

105 – 117

13

Helix

121 – 124

4

Helix

134 – 137

4

Sequences

	Sequence		Length	Mass (Da)
	P00713 [UniParc]. Last modified July 1, 1989. Version 2. Checksum: E13FA2ACA8F1029E	FASTA	142	16,300
	10 20 30 40 50 60 MMSFFPLLLV GILFPAVQAK QLTKCALSHE LNDLAGYRDI TLPEWLCIIF HISGYDTQAI 70 80 90 100 110 120 VKNSDHKEYG LFQINDKDFC ESSTTVQSRN ICDISCDKLL DDDLTDDIMC VKKILDIKGI 130 140 DYWLAHKPLC SDKLEQWYCE AQ

References

[1]	"Structure and expression of the guinea-pig alpha-lactalbumin gene." Laird J.E., Jack L., Hall L., Boulton A.P., Parker D., Craig R.K. Biochem. J. 254:85-94(1988) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA].
[2]	"Comparison of the nucleotide sequence of cloned human and guinea-pig pre-alpha-lactalbumin cDNA with that of chick pre-lysozyme cDNA suggests evolution from a common ancestral gene." Hall L., Craig R.K., Edbrooke M.R., Campbell P.N. Nucleic Acids Res. 10:3503-3515(1982) [PubMed] [Europe PMC] [Abstract] Cited for: NUCLEOTIDE SEQUENCE [MRNA].
[3]	"The complete amino-acid sequence of guinea-pig alpha-lactalbumin." Brew K. Eur. J. Biochem. 27:341-353(1972) [PubMed] [Europe PMC] [Abstract] Cited for: PROTEIN SEQUENCE OF 20-142.
[4]	"Crystal structures of guinea-pig, goat and bovine alpha-lactalbumin highlight the enhanced conformational flexibility of regions that are significant for its action in lactose synthase." Pike A.C.W., Brew K., Acharya K.R. Structure 4:691-703(1996) [PubMed] [Europe PMC] [Abstract] Cited for: X-RAY CRYSTALLOGRAPHY (1.9 ANGSTROMS).

Cross-references

Sequence databases

EMBL
GenBank
DDBJ

J00051 mRNA. Translation: AAA60337.1.
Y00726 Genomic DNA. Translation: CAA68710.1.

PIR

LAGP. S01144.

RefSeq

NP_001166360.1. NM_001172889.1.

3D structure databases

PDBe
RCSB PDB
PDBj

Entry	Method	Resolution (Å)	Chain	Positions	PDBsum
1HFX	X-ray	1.90	A	20-142	[»]

ProteinModelPortal

P00713.

SMR

P00713. Positions 20-142.

ModBase

Search...

Protein-protein interaction databases

STRING

10141.ENSCPOP00000019835.

Protocols and materials databases

StructuralBiologyKnowledgebase

Search...

Genome annotation databases

Ensembl

ENSCPOT00000019635; ENSCPOP00000019835; ENSCPOG00000027342.

GeneID

100379577.

Organism-specific databases

CTD

3906.

Phylogenomic databases

eggNOG

NOG72593.

GeneTree

ENSGT00550000074398.

HOGENOM

HOG000037357.

HOVERGEN

HBG052297.

InParanoid

P00713.

OMA

KCELSQV.

OrthoDB

EOG43JC60.

Family and domain databases

InterPro

IPR001916. Glyco_hydro_22.
IPR019799. Glyco_hydro_22_CS.
IPR000545. Lactalbumin.
IPR023346. Lysozyme-like_dom.
[Graphical view]

PANTHER

PTHR11407:SF5. PTHR11407:SF5. 1 hit.

Pfam

PF00062. Lys. 1 hit.
[Graphical view]

PRINTS

PR00136. LACTALBUMIN.
PR00135. LYZLACT.

SMART

SM00263. LYZ1. 1 hit.
[Graphical view]

SUPFAM

SSF53955. SSF53955. 1 hit.

PROSITE

PS00128. LACTALBUMIN_LYSOZYME_1. 1 hit.
PS51348. LACTALBUMIN_LYSOZYME_2. 1 hit.
[Graphical view]

ProtoNet

Search...

Other

EvolutionaryTrace

P00713.

Entry information

Entry name

LALBA_CAVPO

Accession

Primary (citable) accession number: P00713

Entry history

Integrated into UniProtKB/Swiss-Prot:	July 21, 1986
Last sequence update:	July 1, 1989
Last modified:	April 3, 2013
This is version 98 of the entry and version 2 of the sequence. [Complete history]

Entry status

Reviewed (UniProtKB/Swiss-Prot)

Annotation program

Chordata Protein Annotation Program