AI Article Synopsis
- A marine bacterium identified as Aeromonas salmonicida subsp. was found to produce a specific alanine-targeting enzyme, aminopeptidase K, through isolation from marine soil.
- The enzyme was purified using techniques like ammonium sulfate fractionation and chromatography, resulting in a highly purified product with a molecular mass of 520 kDa and a complex structure made of six subunits.
- Characterization revealed its optimal activity at pH 6.5 and 45°C, with specific inhibition by various chemicals, and demonstrated a high affinity for the substrate L-Ala-beta-naphthylamide, scoring a K(m) of 0.28 mM and Vmax of 49.4 mumol/min/m
Article Abstract
A protamine-degrading marine bacterium was isolated from marine soil and identified as Aeromonas salmonicida subsp. based on its taxonomical characteristics. An alanine-specific aminopeptidase, called aminopeptidase K, from an extract of the strain was purified and characterized. The aminopeptidase K was purified about 80-fold by fractionation with ammonium sulfate and column chromatography on QA-52 cellulose, Phenyl Superose and Superose 12. The purified enzyme is composed of 6 subunits of 86 kDa with a molecular mass of 520 kDa according to gel filtration and SDS-PAGE. The N-terminal sequence of the enzyme was H.Gly-Gln-Gln-Pro-Gln-Ile-Lys-Try-Tyr-His-Asp-Tyr-Asp-Ala-Pro-Asp-Tyr-Ty r- Ile-Thr-. It is inhibited by monoiodoacetate, N-ethylmaleimide, and puromycin. The Michaelis constant (K(m)) and the maximal rate of hydrolysis (Vmax) were, respectively, 0.28 mM and 49.4 mumol/min/mg for the L-Ala-beta-naphthylamide substrate. The optimum pH and optimum temperature were 6.5 and 45 degrees C, respectively. The purified enzyme was highly specific to L-Ala-beta-naphthylamide.
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| http://dx.doi.org/10.1271/bbb.61.1102 | DOI Listing |
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Purification and properties of an aminopeptidase from a protamine-degrading marine bacterium.
Biosci Biotechnol Biochem
July 1997
Department of Biotechnology, Faculty of Engineering, Kansai University, Osaka, Japan.
Article Synopsis
- A marine bacterium identified as Aeromonas salmonicida subsp. was found to produce a specific alanine-targeting enzyme, aminopeptidase K, through isolation from marine soil.
- The enzyme was purified using techniques like ammonium sulfate fractionation and chromatography, resulting in a highly purified product with a molecular mass of 520 kDa and a complex structure made of six subunits.
- Characterization revealed its optimal activity at pH 6.5 and 45°C, with specific inhibition by various chemicals, and demonstrated a high affinity for the substrate L-Ala-beta-naphthylamide, scoring a K(m) of 0.28 mM and Vmax of 49.4 mumol/min/m
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