The isolation and some chemical properties of viridicatin, a metabolic product of Penicillium viridicatum Westling.

R. R. PORTER I953 This method could therefore be used as a simple and rapid method of insulin assay, measurement of the area under the peak giving the insulin content ofthe sample used. In addition to speed and simplicity this method has an advantage over biological assay in that it appears to be as satisfactory for crude as for pure insulin. It would be equally possible to use this technique for preparative work, as a single step appears to be sufficient to obtain pure insulin from crude material. The maximum weight used with these columns so far has been 150 mg. crude insulin on a 50 g. column, but there is no evidence that this loading may not be raised.