|Budget Amount *help
¥2,300,000 (Direct Cost : ¥2,300,000)
Fiscal Year 1996 : ¥700,000 (Direct Cost : ¥700,000)
Fiscal Year 1995 : ¥1,600,000 (Direct Cost : ¥1,600,000)
Lactophorin (LP) is a major glycoprotein in the proteose-peptone fraction of bovine milk and constituted of two major glycopeptides (27 and 17 kDa). A cDNA encoding 27 kDa glycopeptide of LP (27kLP) was cloned. It was revealed to consist of 621 bp, which encoded 18 amino acids for signal peptide and 135 amino acids for mature LP.The deduced mature amino acid sequence is identical to that of proteose-peptone component 3 (PPC3), which has recently been chemically determined by Sorensen and Petersen [J.Dairy Res.60,535, (1993)].
LP had the highest emulsifying activity, emulsion stability, and specific surface areas and smallest median diameter of globules in comparison with those of other fractions of proteose-peptone component-3 (PPC3) separated by gel filtration. Emulsions prepared from 1% LP and 25% milk fat had 2500 of emulsifying activity and was highly stable and median diameter of their glubules was 2.45mum and their specific surface area was 31.7x10^3cm^2/cm^3. In addition, increasing of LP content up to 60 mg/g of milk fat in emulsion increased emulsifying activity, emulsion stability, and specific surface areas and decreased median diameter. Emulsifying ability of LP is discussed from the distribution of hydrophobic amino acid residues in the primary structure and in alpha-helical wheel of the secondary structure of LP.