Production of L-leucine aminopeptidase by selected Streptomyces isolates

Abstract

Aims: To screen various Streptomyces cultures producing l‐leucine aminopeptidase (LAP). Methods and Results: Twenty‐one Streptomyces strains were screened for LAP production. The best three producers were found to be Streptomyces mobaraensis NRRL B‐3729, Streptomyces gedanensis IFO 13427, and Streptomyces platensis NRRL 2364. pH optima of the three enzymes were in the range of 8·0–8·5 and the temperature optima varied between 50 and 65°C. LAP of S. mobaraensis was stable at 60°C and pH 8·5 for 60 min. Metal ion salts, CoCl2.6H2O and ZnSO4.7H2O in 0·7 mmol l−1 concentration enhanced the relative enzyme activity in all three enzymes. Molecular mass of LAP of S. mobaraensis was found to be approx. 37 kDa. Conclusions: Streptomyces mobaraensis NRRL B‐3729, S. gedanensis IFO 13427, and S. platensis NRRL 2364 were found to be good producers of extracellular LAP. The approx. 37 kDa enzyme of S. mobaraensis is considerably thermostable. Significance and Impact of the Study: A good number of Streptomyces were screened and the ability of the aminopeptidases to release a particular N‐terminal amino acid along with its good thermal stability makes them interesting for controlling the degree of hydrolysis and flavour development for a wide range of substrate.

Development of a High-Throughput Screening Assay to Identify Inhibitors of the Major M17-Leucyl Aminopeptidase from Trypanosoma cruzi Using RapidFire Mass Spectrometry

“…M17-LAPs are usually assayed at alkaline pH and elevated temperature, 29,[31][32][33][34] and the T. cruzi enzyme displays maximal activity at pH 9.0 and 50 C. 24 Although these conditions are incompatible with HTS, LAPTc retained sufficient activity at pH 7.5 and room temperature for HTS assay development (Figs. 1A, 2A, and 2C).…”

Purification and Biochemical Characterization of Methionine Aminopeptidase (MetAP) from Mycobacterium smegmatis mc2155

“…The staining was very sensitive as it could detect the enzyme band even at higher enzyme dilutions up to 10 −4 U. However, the renaturation of enzyme from denaturing SDS-PAGE by treating with 2.5% Triton ×-100, as reported for other aminopeptidases [21], was not possible in this case. The protein showed a higher molecular weight on a native gel, which may be attributed to the multimeric nature of protein for its function.…”

A New Aminopeptidase from the Keratin-Degrading Strain Streptomyces fradiae var. k11

“…SFAP also showed pH stability over a wide pH range, retaining over 50% of the initial activity after pre-incubation at pH 3.0-11.0. These superior properties make S. fradiae AP more potential in research and industrial processes [23]. Moreover, the enzymatic properties of SFAP might be improved by protein engineering.…”