L-(+)-Cysteine → (2R)-2-Acetamido-3-({(2R,3S,4R)-3-hydroxy-2-[(1S)-1-hydroxy-2-methylpropyl]-4-methyl-5-oxopyrrolidine-2-carbonyl}sulfanyl)propanoic acidLactacystin

Participants

Reaction Steps

COS cells were plated onto 100 mm dishes, then, with DEAE-Destran, either mock transfected, or transfected with 3 μg of pcDNA plasmid containing the human p105 cDNA. Forty-eight hrs after transfection, cells were pretreated for 1 hour with 0.5% DMSO, 50 μM calpain inhibitor II, 50 μM MG132, or 10 μM β-lactone. Cells were then pulse labelled with 250 uCi/plate of 35S-methionine/cysteine for 15 minutes, and either harvested immediately or followed by a 2 hour chase with excess unlabelled methionine and cysteine. Cells were then lysed with SDS/Tris, and proteins were immunoprecipitated with anti-p50 antibodies (recognize the N-terminal half of the p105 protein). These proteins were then separated on a 10% SDS-polyacrylamide gel, which was then fixed, dried, and exposed to autoradiographic film.

Provenance & Evidence