Aminopeptidase I from Streptomyces griseus

General description

Aminopeptidase I from Streptomyces griseus is a thermostable enzyme with Glu131 and Tyr246 as key active site residues.

Application

Aminopeptidase I from Streptomyces griseus has been used:

• to test the biochar exposure effect on the enzyme activity
• in circular dichroism (CD) spectroscopy studies
• as a positive control in p-nitroanilide degradation assay

Biochem/physiol Actions

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.

Aminopeptidase I may also be used as a reagent in the assay of endoprotease activities with a synthetic substrate in a two-stage assay. In the first stage, the endoprotease cleaves a peptide, such as Z-Y-X-Leu-p-nitroanilide, with the X, Y, and Z residues being chosen according to the specificity of the endoprotease.

Packaging

Package size based on protein content.

Unit Definition

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 Â°C and 3.0 mM substrate concentration.

Physical form

Contains calcium acetate

Preparation Note

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.

Other Notes

Endopeptidase contaminant: Not more than: 0.01 U/mg protein (as μmole tyrosine equivalent per min released from casein.)