An important step in the protocol: “Disposable Polymeric Cryogel Bioreactor Matrix for Therapeutic Protein Production”, is testing the circulating media at regular time intervals to analyze for glucose, lactic acid, and the protein of interest being secreted by the cells.
In this Exchange Protocol we describe our method for determining the concentration of urokinase, an example protein of interest.
Urokinase activity was determined as amidolytic effect on the substrate pyro-Glu-Gly-Arg-p-nitroanilide-HCl. The rate of formation of p-nitroaniline was measure at 405nm using acid stopped method. Urokinase activity vs absorbance correlation is linear between 5-40 Ploug units.