SOURCE. Porcine Stomach Mucosa.SPECIFICATIONS.Crude, highly soluble preparation.Hygroscopic powder, contains ca. 1.0% NaCl.Store at 25° C. Will remain stable 9-12 months with no decrease in activity.2.0-2.5 units per mg of powder.One unit will increase the TCA-soluble peptides from denatured hemoglobin by 1 - A280 per minute at pH 2 and 37° C.