(A) Autoradiograph of SDS-PAGE analysis of total ³⁵S-SO₄–radiolabeled and ³⁵S-methionine/cysteine-radiolabeled protein in the presence (+) or absence (−) of chlorate. Lanes contain equivalent amounts of lysate material obtained from cells cultured at identical density in the presence of respective radiolabels with or without chlorate for the terminal 8 hours of the 24 hours of culture (see text for details). Marked inhibition of sulfation is shown among all sulfated proteins in the presence of chlorate, without significant effects on protein synthesis as shown by equivalent profiles of ³⁵S-methionine/cysteine-radiolabeled proteins. MW markers (in kilodaltons) are shown at the left of the figure. (B) Autoradiograph of SDS-PAGE analysis of ³⁵S-SO₄ metabolically radiolabeled CD43 in presence or absence of chlorate. CD43 was immunoprecipitated from lysates representing equivalent numbers of chlorate-treated or control (untreated) KG1a cells that were incubated with ³⁵S-SO₄ for the terminal 8 hours of the 24 hours of culture. Immunoprecipitations with anti-CD43 or isotype control MoAbs are as noted above each lane; numbers at left are MW markers in kilodaltons. Markedly diminished levels of ³⁵SO₄-labeled CD43 are evident in the chlorate-treated cell population.