|Ref Sequence Id||NP_776803.1|
|Amino Acid Lenth||142|
|Protein Existence Status||Reviewed: Experimental evidence at protein level|
|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) |
|>sp|P00711|LALBA_BOVIN Alpha-lactalbumin OS=Bos taurus OX=9913 GN=LALBA PE=1 SV=2
MMSFVSLLLVGILFHATQAEQLTKCEVFRELKDLKGYGGVSLPEWVCTTF HTSGYDTQAIVQNN*64DSTEYGLFQINNKIWCKDDQNPHSSNICNISCDKFL DDDLTDDIMCVKKILDKVGINYWLAHKALCSEKLDQWLCEKL
|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.
9. Nurminen ML, Sipola M, Kaarto H, Pihlanto-Leppälä A, Piilola K, Korpela R, et al. α-Lactorphin lowers blood pressure measured by radiotelemetry in normotensive and spontaneously hypertensive rats. Life Sci. 2000 Mar 10;66(16):1535–43.