Characterisation of proteins in the milk of fur seals

• Main Authors: K Cane, John Arnould, Kevin Nicholas
• Format: Other Non-Article Part of Journal/Newspaper
• Language: unknown
• Published: 2005
• Subjects: Physiology; beta-lactoglobulin; casein; fur seal; lactation; milk composition; protein sequence; whey; Science & Technology; Life Sciences & Biomedicine; Biochemistry & Molecular Biology; Zoology; BOVINE BETA-LACTOGLOBULIN; SOUTHERN ELEPHANT SEAL; FATTY-ACID-COMPOSITION; WHEY PROTEINS; SECRETION; RETINOL; BINDING; IDENTIFICATION; SUPERFAMILY; Antarctic; The Antarctic; Antarc*; Antarctic Fur Seal; Arctocephalus gazella; Elephant Seal; Southern Elephant Seal
• Online Access: http://hdl.handle.net/10536/DRO/DU:30008863; https://figshare.com/articles/journal_contribution/Characterisation_of_proteins_in_the_milk_of_fur_seals/20559402

Milk protein composition was investigated throughout the lactation periods of the Australian fur seal ( Arctocephalus pusillus doriferus ) and Antarctic fur seal ( Arctocephalus gazella ). The mean protein content of the milk was found to be 10.9% and 10.6% respectively. The concentration of total protein did not change during lactation, although a decline in casein content of the milk in late lactation was apparent. Milk protein concentration during a foraging/suckling cycle of the Antarctic fur seal analysed at the time of arrival on shore, and 24 h and 72 h after arrival was 12.8%, 11.4% and 12.5% respectively. Re-feeding animals at 72 h resulted in a significant increase in milk protein content to 14.9%. Characterisation of milk protein by SDS-PAGE analysis revealed 5 casein and 10 major whey protein bands. Amino-terminal sequencing indicated that the majority of the whey fraction of the milk is β-lactoglobulin (β-LG). The limited amino acid sequence indicated 3 different β-LGs were secreted in the milk. Subsequently, RT-PCR was used to extend the sequence of one of the β-LGs and translation of the 464 bp fragment indicated that it shared 79% sequence identity with feline β-LG II.