Primary Information | |
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BoMiProt ID | Bomi98 |
Protein Name | Alpha-lactalbumin |
Organism | Bos taurus |
Uniprot ID | P00711 |
Milk Fraction | Whey |
Ref Sequence ID | NP_776803.1 |
Aminoacid Length | 142 |
Molecular Weight | 16247 |
FASTA Sequence | Download |
Gene Name | LALBA |
Gene ID | 281894 |
Protein Existence Status | Reviewed: Experimental evidence at protein level |
Secondary Information | |
Endogenous/Bioactive peptides - Fragment - Sequence - Effect | Lactorphines - 50–53 - YGLF - Opioid agonist ACE inhibition Ref Lactokinins - ACE inhibitory Ref |
Protein Function | Inhibits the formation of N-acetyllactosamine; reduction of stress; antimicrobial activity; opioid activity; antihypertensive action; regulation of cells growth; antiulcer activity and immunomodulation; |
Biochemical Properties | acidic, compact globular structure stabilized by four disulfide bonds; metalloprotein with a single Ca2+ binding site; isoelectric point of 4.6; has no free thiol groups; genetically and structurally homologous to c-type lysozyme; has two predominant genetic variants (A and B); The B variant is present in the milk of most Bos taurus cattle, and both the A and B variants are found in the milk of Bos indicus cattle; Both A and B variant contain four disulfide bonds and no phosphate groups; the tertiary structure of LA is composed of a large domain (α) with pH stable α helices and a small domain (β) divided by a cleft; partially folded intermediate states; acidic pH and in the apo-state at elevated temperatures LA is the classic molten globule which is highly stable; Calcium binding strongly influences the molecular stability of LA and is required for refolding and native disulfide bond formation in the reduced, denatured protein; Removal of Ca2+ from the protein enhances its sensitivity to pH and ionic conditions due to noncompensated negative charge-charge interactions at the cation binding site, which significantly reduces its overall stability; At neutral pH and low ionic strength, the native structure of apo-LA is stable below 140C and undergoes a conformational change to a native-like molten globule intermediate at temperatures above 250C; difficult to hydrolyse; highly resistant to tryptic digestion |
Significance in milk | LA has a high content of lysine and cysteine and a particularly high content of tryptophan; between bovine and human milks are the lower concentrations of tryptophan and cysteine in the latter; a critical factor in the nutrition of neonates in general and premature neonates; The high content of cysteine in LA is also valuable in boosting the immune system and promoting wound healing. LA also has a high level of tryptophan, which may help improve mood, sleep and cognitive performance; |
PTMs | A small percentage of the LA found in the milk of cattle is glycosylated on an Asn residue; presence of neutral sugars such as mannose, galactose and fucose, aminosugars such as glucosamine and galactosamine, presence of N-Acetylneuraminic acid and N-Glyeolloylneuraminic acid |
Site(s) of PTM(s) N-glycosylation, O-glycosylation, Phosphorylation | >sp|P00711|LALBA_BOVIN Alpha-lactalbumin OS=Bos taurus OX=9913 GN=LALBA PE=1 SV=2
MMSFVSLLLVGILFHATQAEQLTKCEVFRELKDLKGYGGVSLPEWVCTTF HTSGYDTQAIVQNN*64DSTEYGLFQINNKIWCKDDQNPHSSNICNISCDKFL DDDLTDDIMCVKKILDKVGINYWLAHKALCSEKLDQWLCEKL |
SCOP | Class : Alpha and beta proteins (a+b) Fold : Lysozyme-like Superfamily : Lysozyme-like Family : C-type lysozyme Domain Name : 1F6S A:1-122 |
CATH | Matched CATH superfamily 1.10.530.10 |
Predicted Disorder Regions | NA |
DisProt Annotation | |
TM Helix Prediction | No TM helices |
PDB ID | 1F6R, 1F6S, 1HFZ, 2G4N, 6IP9, |
Bibliography | 1. Barman, T. E. (1970). Purification and properties of bovine milk glyco-alpha-lactalbumin. Biochimica et Biophysica Acta, 214(1), 242–244. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/5488946. 2. Universitatea Dunărea de Jos Galați. (n.d.). The Annals of the University Dunarea de Jos of Galati. Fascicle VI, Food technology. Retrieved from http://agris.fao.org/agris-search/search.do?recordID=DJ2012060152. 3. Permyakov, E. A., Shnyrov, V. L., Kalinichenko, L. P., Kuchar, A., Reyzer, I. L., & Berliner, L. J. (1991). Binding of Zn(II) ions to alpha-lactalbumin. Journal of Protein Chemistry, 10(6), 577–584. https://doi.org/10.1007/bf01025709. 4. Ghosh, B. C., Prasad, L. N., & Saha, N. P. (2017). Enzymatic hydrolysis of whey and its analysis. Journal of Food Science and Technology, 54(6), 1476–1483. https://doi.org/10.1007/s13197-017-2574-z. 5. Sitohy, M., Chobert, J. M., & Haertlé, T. (2001). Susceptibility to trypsinolysis of esterified milk proteins. International Journal of Biological Macromolecules, 28(4), 263–271. Retrieved from http://www.ncbi.nlm.nih.gov/pubmed/11311716. 6. Sternhagen, L. G., & Allen, J. C. (2001). Growth rates of a human colon adenocarcinoma cell line are regulated by the milk protein alpha-lactalbumin. Advances in Experimental Medicine and Biology, 501, 115–120. https://doi.org/10.1007/978-1-4615-1371-1_14. 7. Svensson, M., Håkansson, A., Mossberg, A. K., Linse, S., & Svanborg, C. (2000). Conversion of alpha-lactalbumin to a protein inducing apoptosis. Proceedings of the National Academy of Sciences of the United States of America, 97(8), 4221–4226. https://doi.org/10.1073/pnas.97.8.4221. 8. Yamaguchi, M., & Uchida, M. (2007). Alpha-lactalbumin suppresses interleukin-6 release after intestinal ischemia/reperfusion via nitric oxide in rats. Inflammopharmacology, 15(1), 43–47. https://doi.org/10.1007/s10787-006-1558-9. |