Figure 7.

Instrumental background levels relative to the sample signal for dilutions of glucose isomerase. The high-pressure cell was replaced with a vacuum pipe to obtain a ‘windowless background’ profile. Diamond windows were measured in situ by emptying the cell of its pressurization water and drying. The artifactual ring at q = 0.11 is some residual silver behenate standard. Guinier analysis of the 4.5 mg ml⁻¹ sample has a relative error in R _g of 0.3%, while analysis of the dilute sample (0.9 mg ml⁻¹) yields a relative error of 1%.