Fig. 3.

Enrichment in D2 activity with purification of microsomal fractions of red and white skeletal muscle. Muscles were obtained from eight mice and fractionated following the improved method schematically shown on the right panel of Fig. 1. Table 1 shows the recovery of protein from the original material. Fractions were assayed in triplicate with approximately 1.5 nm ¹²⁵-I-rT₃. Reaction time was shortened to 15 min based on time-course studies described in the text and illustrated in Fig. 4.