Proteomic analysis of whey and casein proteins in early milk from the marsupial Trichosurus vulpecula, the common brushtail possum.
Whey and casein proteins representing the first and second halves of the early lactation phase in the common brushtail possum (Trichosurus vulpecula) have been compared by two dimensional gel electrophoresis. Nine components of whey were differentially expressed during early lactation, including proteins identified as cathepsin B, clusterin, late lactation protein, lysozyme, ganglioside M2 activator and neutrophil gelatinase-associated lipocalin. A major novel protein, termed very early lactation protein (VELP), was identified in whey. Partial amino acid sequence data obtained from VELP did not appear to match any other reported protein sequence. VELP was shown to be an acidic glycoprotein of 20-30 kDa which exists as a homodimer. In the casein fraction, kappa-casein appeared to be differentially post-translationally modified during early lactation and fragments of beta-casein were relatively more abundant at the earlier lactation stage.
Kuy
Sulee
S
School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland Mail Centre, Auckland 1142, New Zealand.
Kelly
Van C
VC
Smit
Anne-Marie
AM
Palmer
David J
DJ
Cooper
Garth J
GJ