title: The development of cytochrome b-245 in maturing human macrophages.
abstract: Cytochrome b-245, the putative terminal component of the specialized cidal oxidase system of phagocytes, was measured in human monocytes in culture. There was a dramatic synthesis of the cytochrome, which increased by 27.3 +/- 2.0 pmol/day per 10(7) cells. This represents an increase of about 40%/day in the early stages and an overall 7-fold increase after 16 days. The protein content increased 3-fold over the same period, resulting in a doubling of the specific content of the cytochrome b. The newly synthesized cytochrome b was identified as that specifically located in the microbicidal oxidase electron-transport chain, as titration demonstrated that, at day 16 of maturation, 70% of the total membrane cytochrome b had a very low midpoint potential (-260 to -220 mV), characteristic of that found in this oxidase system. This cytochrome distributed with the plasma membrane on analytical subcellular fractionation, and a close relationship was observed between the maturation-induced increase in the concentration of this molecule and the capacity of the cells to produce superoxide.
mesh_terms: D001798:Blood Proteins / Q000378:metabolism; D002478:Cells, Cultured; D002500:Centrifugation, Isopycnic; D003573:Cytochrome b Group / Q000097:blood*; D006801:Humans; D006867:Hydrolases / Q000097:blood; D008264:Macrophages / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism; D013481:Superoxides / Q000097:blood
chemical_list: D001798:Blood Proteins; D003573:Cytochrome b Group; C035130:cytochrome b245; D013481:Superoxides; D006867:Hydrolases