Alpha-lactalbumin as a lysosomal enzyme-releasing factor.
In the early stage of mammary gland involution, biochemically detectable lysosomal damage occurs. The mechanism(s) underlying this damage is not well understood. We found that alpha-lactalbumin from mouse milk induced the release of enzymes from the lysosomes of mouse mammary epithelial cells in vitro, and this induction also occurred with bovine alpha-lactalbumin. This enzyme release was accelerated by the addition of whey proteins with a molecular weight of 50 000 to 60 000. We also found that the lysosomal membrane of mammary epithelial cells had a strong affinity for alpha-lactalbumin.
D000818:Animals; D002417:Cattle; D002846:Chromatography, Affinity; D004589:Electrophoresis, Disc; D005260:Female; D005966:Glucuronidase / Q000378:metabolism; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism; D007768:Lactalbumin / Q000302:isolation & purification / Q000502:physiology*; D007785:Lactose / Q000032:analysis; D008247:Lysosomes / Q000201:enzymology*; D008321:Mammary Glands, Animal / Q000201:enzymology / Q000648:ultrastructure*; D051379:Mice; D008813:Mice, Inbred ICR; D008892:Milk / Q000032:analysis; D008995:Monoamine Oxidase / Q000378:metabolism; D011485:Protein Binding; D011506:Proteins / Q000494:pharmacology; D013347:Subcellular Fractions / Q000201:enzymology
D011506:Proteins; D007768:Lactalbumin; D008995:Monoamine Oxidase; D005966:Glucuronidase; D007785:Lactose