Figure 3.

Reversed-phase HPLC separation of a tryptic digest of bromo[1-¹⁴C]acetate alkylated ⁷⁵Se-labeled TR from HeLa cells. Conditions for alkylation, digestion with trypsin, and HPLC separation are described in Materials and Methods. Solid circles, ¹⁴C radioactivity; open circles, ⁷⁵Se radioactivity. (A) Edman degradation profile of ¹⁴C [solid bars] and ⁷⁵Se [open bars] recovered at each sequencer cycle from the major tryptic peptide eluted in fractions 96–97. (B) Profile as above from a minor peptide eluted in fractions 91–92. The amino acid identified in each cycle of A and B, shown in the line between the inserts, is the same as the predicted sequence of human placenta TR (5).