Figure 9.

The hBMP2 active domain is efficiently released from zein-hBMP2ad by thrombin cleavage. Twenty-five micrograms of total leaf proteins, extracted in the presence of 2-ME from zein-hBMP2ad transgenic (lines #7 and 27) or wt plants, were incubated for 20 h in the presence (+) or absence (−) of thrombin. The reaction mixtures were analyzed by SDS-PAGE, followed by protein blot using anti-Flag antiserum. hBMP2ad was quantified by comparison with known amounts of the commercial standard protein Flag–BAP (lanes on the left). Empty circles: 20 kD hBMP2ad. Asterisks: 18 kD fragment of hBMP2ad. Numbers at left indicate the position of the molecular weight markers, in kDa.