Cytosolic catabolites of H+-ATPase in senescing carnation petals.
Hudak, K.A., Ghosh, S., Dumbroff, E.B., and Thompson, J. E.
Phytochemistry. Volume 44, Number 3, Feb 1997. Pages 371-376.
1997
บทคัดย่อ
The localisation of H+-ATPase catabolites in subcellular fractions isolated from carnation petals has been determined immunologically using two antibodies, one raised against a mid-section of the protein (amino acids 340-650) and the other corresponding to the C-terminus. The native Mr 100000 polypeptide of the H+-ATPase was clearly discernible in Western blots of microsomal membranes probed with either antibody; each antibody also depicted a distinguishable pattern of lower abundance catabolites of the protein in microsomal membranes. Some of these catabolites were present in the cytosolic fraction as well, in higher abundance than in microsomal membranes. The antibodies also depicted distinguishable patterns of other catabolites of the H+ATPase in the cytosol that were not present in microsomal membranes and that changed with advancing senescence of the petals. Immunocytochemical localization of the H+-ATPase and its catabolites using the antibody specific to the C-terminus showed staining of the cytoplasm as well as the plasma membrane. Moreover, the cytosolic H+-ATPase catabolites contain membrane-spanning domains of the protein and coeluted with phospholipid during Sephadex G-25 gel filtration. These observations indicate collectively that catabolites of the H+-ATPase formed within the plasma membrane are subsequently released into the cytosol, possibly in association with lipid.