Streptomyces griseus aminopeptidase is a calcium-activated zinc metalloprotein. Purification and properties of the enzyme.
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Spungin A, Blumberg S
Streptomyces griseus aminopeptidase is a calcium-activated zinc metalloprotein. Purification and properties of the enzyme.
Eur J Biochem. 1989 Aug 1;183(2):471-7.
- PubMed ID
- 2503378 [ View in PubMed]
- Abstract
A heat-stable aminopeptidase with an N-terminal Ala-Pro-Asp-Ile-Pro-Leu sequence has been purified from Streptomyces griseus by heat treatment followed by gel-exclusion and anion-exchange chromatographic procedures. The enzyme is a monomeric zinc metalloenzyme showing an apparent molecular mass of 33 kDa by sodium dodecyl sulfate/polyacrylamide gel electrophoresis and 21 kDa by gel filtration on Superose 12. Calcium ions bind to the enzyme, pKCa 4.5, and activate it about sixfold when the substrate is leucine-4-nitroanilide (0.4 mM in 50 mM Tris/HCl pH 8.0, 25 degrees C). Binding of Ca2+ also contributes to the thermal stability of the protein. This aminopeptidase may be useful for two-stage assays of bacterial and mammalian metalloendopeptidases; it may also serve in studies of proteolytic enzyme activation by calcium ions.