Description_x000D_ Application_x000D_ Aminopeptidase I from Streptomyces griseus may be used as a reagent for the analysis of protein structure and as a model for studies of proteolytic enzyme activation by calcium ions. It may be used as a reagent in the assay of endoprotease activities with a synthetic substrate in a two-stage assay . The lyophilized powder also contains calcium acetate._x000D_ Packaging_x000D_ 0.1 mg in serum bottle_x000D_ Biochem/physiol Actions_x000D_ Aminopeptidase I from S. griseus has a fairly broad specificity, being able to remove the N-terminal residue of most proteins, except where the penultimate residue is an imino acid. It contains two Zn2+ binding sites. Aminopeptidase I from S. griseus is inhibited by 1,10-phenanthroline and is activated six-fold by Ca2+, which also stabilizes it against heat inactivation. This monomeric zinc metalloprotein has an isoelectric point (pI) of 5.4._x000D_ Packaging_x000D_ Package size based on protein content._x000D_ Unit Definition_x000D_ One unit will hydrolyze 1.0 μmole of L-leucine-p-nitroanilide to L-leucine and p-nitroaniline per min at pH 8.0, 25 °C and 3.0 mM substrate concentration._x000D_ Physical form_x000D_ Contains calcium acetate_x000D_ Preparation Note_x000D_ Reconstitute in 20 mM tricine, pH 8.0, with 0.05% bovine serum albumin. Dilute the enzyme with the reconstitution buffer to 0.15-0.3 U/mL for a working concentration. Solutions should be prepared fresh prior to use._x000D_ Other Notes_x000D_ Endopeptidase contaminant: Not more than: 0.01 U/mg protein (as μmole tyrosine equivalent per min released from casein.)