Isolation, partial sequence and asynchronous appearance during lactation of lysozyme and alpha-lactalbumin in the milk of a marsupial, the common ringtail possum (Pseudocheirus peregrinus).
1. Lysozyme and alpha-lactalbumin from the milk of the common ringtail possum have been purified and partially sequenced. 2. The lysozyme had similar enzymic activity to the c-type lysozyme of the domestic hen and 43% homology over the N-terminal 49 residues. 3. alpha-Lactalbumin was present in the milk in two biologically active forms; the more acidic form had 66% sequence homology with the N-terminal 35 residues of red-necked wallaby, 54% with human and 43% with bovine alpha-lactalbumin. 4. SDS polyacrylamide-gel electrophoresis of milk samples showed that alpha-lactalbumin was present in the milk throughout lactation but that lysozyme first appeared only in mid-lactation. The implications of this functional adaptation are discussed.
Nicholas
K
K
Division of Wildlife and Ecology, CSIRO, Lyneham, ACT, Australia.
Loughnan
M
M
Messer
M
M
Munks
S
S
Griffiths
M
M
Shaw
D
D
D000595:Amino Acid Sequence; D000818:Animals; D005260:Female; D007768:Lactalbumin / Q000302:isolation & purification / Q000378:metabolism*; D007774:Lactation / Q000378:metabolism; D008892:Milk / Q000201:enzymology / Q000378:metabolism*; D008969:Molecular Sequence Data; D009113:Muramidase / Q000302:isolation & purification / Q000378:metabolism*; D009893:Opossums / Q000378:metabolism*; D011247:Pregnancy
D007768:Lactalbumin; D009113:Muramidase