title: Effect of stages of lactation on the concentration of a 90-kilodalton heat shock protein in bovine mammary tissue.
abstract: From the normal mammary tissue of a Holstein cow in late lactation, a heat shock protein (90 kDa) was purified by ammonium sulfate fractionation and five-step column chromatography. From 70 g of tissue, 9.5 mg of this heat shock protein were obtained; samples had 98% purity and 19% recovery. The molecular mass of the 90-kDa heat shock protein was estimated to be 86 kDa by SDS-PAGE. Analysis of the amino-terminal amino acid sequence suggested that the protein had been purified as a mixture of two isoforms. The contents of the heat shock protein in cytoplasmic fractions of mammary tissues from Holstein heifers and cows at lactation and involution were measured by quantitative immunoblot analysis using rabbit antiserum raised against the purified heat shock proteins. The contents of the heat shock protein were higher in tissues from lactating cows than in those from heifers and involuting cows. The elevated concentrations of cytoplasmic 90-kDa heat shock protein in lactating tissue suggested that this protein is involved in mammary differentiation and lactation.
authors.affiliation: Hokkaido Branch Laboratory, National Institute of Animal Health, Sapporo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Watanabe
authors.forename: T
authors.initials: T
authors.lastname: Miyamoto
authors.forename: N
authors.initials: N
authors.lastname: Katoh
authors.forename: Y
authors.initials: Y
authors.lastname: Takahashi
mesh_terms: D000595:Amino Acid Sequence; D000645:Ammonium Sulfate; D000818:Animals; D000911:Antibodies, Monoclonal; D002417:Cattle / Q000378:metabolism*; D005591:Chemical Fractionation; D002845:Chromatography; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D018841:HSP90 Heat-Shock Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D007774:Lactation / Q000502:physiology*; D008321:Mammary Glands, Animal / Q000378:metabolism*; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D017421:Sequence Analysis
chemical_list: D000911:Antibodies, Monoclonal; D018841:HSP90 Heat-Shock Proteins; D000645:Ammonium Sulfate