| Popis: |
The diffusion of oxyleghaemoglobin, prepared from soybean root nodules, was measured at 24°C in agar and agarose gels of various strengths, or in 1% agarose containing 0-18% (w/v) bovine serum albumin, to simulate the protein content of the cytoplasm of root nodule cells. Values of Dp, the diffusion coefficient, were unaffected (Dp = 11·8 × 10-11 m2 s-1; s.e.m. 0·3 × 10-11) until the protein concentration exceeded 6%, above which Dp declined sharply. With 18% bovine serum albumin, the concentration of total soluble protein calculated to be present in the cytoplasm of infected cells, where most of the leghaemoglobin is located in vivo, Dp was 5·9 × 10-11 m2 s-1. These results are discussed in relation to leghaemoglobin-facilitated delivery of O2 to the respiring N2-fixing bacteroids in root nodule cells. |
