SOURCE. Porcine Stomach Mucosa.SPECIFICATIONS.Highly purified by crystallization and chromatography of P715. Salt-free, highly soluble lyophilized white powder.Store at 25° C. Stable 9-12 months with no decrease in activity.4.0-5.1 units per mg of protein.One unit will increase the TCA-soluble peptides by - A280 per minute in 0.01 M HCI at 37° C from denatured hemoglobin.