Table 2.

Elution of plasma inhibitory activity from solid‐phase extraction columns

Column	Effect on ACE2
Reverse‐phase (C18 Sep‐pak)
Fraction 1 (non‐retained)	Inhibition
Fraction 2 (non‐retained)	Inhibition
Fraction 3 (wash)	No inhibition
Fraction 4 (wash)	No inhibition
Fraction 5 (retained)	No inhibition
Fraction 6 (retained)	No inhibition
Size exclusion (PD‐10)
Fraction 1	No inhibition
Fraction 2	No inhibition
Fraction 3	No inhibition
Fraction 4	Inhibition
Fraction 5	Inhibition
Fraction 6	No inhibition
Anion exchange (ANX)
Fraction 1 (non‐retained)	Inhibition
Fraction 2 (wash)	No inhibition
Fraction 3 (high salt elution)	No inhibition
Cation exchange (SP)
Fraction 1 (non‐retained)	No inhibition
Fraction 2 (wash)	No inhibition
Fraction 3 (high salt elution)	No inhibition