Cane K N, Arnould J P Y, Nicholas K R
CRC for Innovative Dairy Products, Department of Zoology, University of Melbourne, Victoria 3010, Australia.
Comp Biochem Physiol B Biochem Mol Biol. 2005 May;141(1):111-20. doi: 10.1016/j.cbpc.2005.02.003.
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 beta-lactoglobulin (beta-LG). The limited amino acid sequence indicated 3 different beta-LGs were secreted in the milk. Subsequently, RT-PCR was used to extend the sequence of one of the beta-LGs and translation of the 464 bp fragment indicated that it shared 79% sequence identity with feline beta-LG II.
对澳大利亚海狗（Arctocephalus pusillus doriferus）和南极海狗（Arctocephalus gazella）整个哺乳期的乳蛋白组成进行了研究。发现乳汁的平均蛋白质含量分别为10.9%和10.6%。尽管在哺乳期后期乳汁中酪蛋白含量明显下降，但总蛋白浓度在哺乳期没有变化。对南极海狗上岸时、上岸后24小时和72小时的觅食/哺乳周期内的乳蛋白浓度进行分析，结果分别为12.8%、11.4%和12.5%。在72小时对动物重新喂食导致乳蛋白含量显著增加至14.9%。通过SDS-PAGE分析对乳蛋白进行表征，发现有5条酪蛋白带和10条主要乳清蛋白带。氨基末端测序表明，乳汁中大部分乳清部分是β-乳球蛋白（β-LG）。有限的氨基酸序列表明乳汁中分泌了3种不同的β-LG。随后，使用RT-PCR扩展其中一种β-LG的序列，对464 bp片段的翻译表明它与猫β-LG II的序列同一性为79%。
