Characterization of N-ethylmaleimide-reactive proteins from human tonsillar ribosomes by two-dimensional polyacrylamide gel electrophoresis.
Human tonsillar 80-S ribosomes were 17% and 43% inactivated by 1 mM N-ethylmaleimide after 12 min at 30 or 37 degrees C, respectively. The ribosomes were unaffected by the reagent during the same period of time at 0 or 20 degrees C. 4, 12, 27 and 59 sulfhydryl groups per 80-S ribosomes were found labeled by 1 mM N-ethyl[14C] maleimide after 12 min at 0, 20, 30 or 37 degrees C, respectively. The analysis of radioactively labeled proteins by two-dimensional gel electrophoresis revealed the following: after 3 min at 37 degrees C only two 40-S proteins, S3 and S7, displayed a significant amount of label. After 12 min at 37 degrees C, there was a several-fold increase in the extent of radioactivity found in each of these proteins and, additionally, S1, S2, S4, S5, S15, S22 and S31 were also found among labeled 40-S proteins. S3 appeared to be the most N-ethylmaleimide-reactive 40S protein. After 3 min at 37 degrees C, L10, L17, L20 (and/or S20), L26, L32 and L33, and after 12 min at 37 degrees C, additionally L1, L2, L7, L9, L11, L15, L16, L18, and L25 were labeled among 60-S proteins. l17 and 32 were the most N-ethylmaleimide-reactive proteins under these conditions. After 12 min at 37 degrees C, approx. 26% and 39% of the radioactivity incorporated into the 80 S or 60 S ribosomal protein, respectively, was found in these two proteins. After 12 min at 0 degrees C, S3, L17, L32 and L33 were the only labeled proteins.
D004591:Electrophoresis, Polyacrylamide Gel; D005033:Ethylmaleimide / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008970:Molecular Weight; D014066:Palatine Tonsil / Q000378:metabolism*; D010445:Peptide Elongation Factors / Q000378:metabolism; D014176:Protein Biosynthesis / Q000187:drug effects; D012269:Ribosomal Proteins / Q000032:analysis* / Q000378:metabolism; D012270:Ribosomes / Q000187:drug effects / Q000378:metabolism; D013696:Temperature
D010445:Peptide Elongation Factors; D012269:Ribosomal Proteins; D005033:Ethylmaleimide