Figure 4.

Chromatofocusing of FPE. Approximately 500 pituitaries were extracted twice with 0.5 ml 25 mM Bis-Tris-Cl (pH 6.3) and the extracts were combined, centrifugally filtered, and applied to a Mono P column via the 10ml Superloop. After the absorbance recording returned to the baseline (tracing not shown; no gonadotropic activity was present in collected fractions), 10% Polybuffer 74 was pumped onto the column via the 50ml Superloop and this was followed by a salt wash. The effluent was monitored for absorbance at 280 nm. Two-ml fractions were collected and measured for pH. Several fractions (indicated as I-V) were also pooled and subjected to further hydrophobic-interaction chromatography.