Corrigendum: Characterization of ML-005, a Novel Metaproteomics-Derived Esterase

Abstract

[This corrects the article DOI: 10.3389/fmicb.2018.01925.].

Keywords: biocatalysis; esterase; lipase; metagenomics; metaproteomics.

Figure 5

(A) Michaelis-Menten kinetics were observed for ML-005 with pNP-butyrate. V_maxof ML-005 was determined to be 59.8 μM/min along with a K_m of 137.9 μM. The k_cat of ML-005 is 26 s⁻¹and k_cat/K_m is 1.88 × 10⁵ M⁻¹ s⁻¹. (B) ML-005 showed temperature tolerance from 20 to 60°C. (C) ML-005 showed tolerance over a broad range of pH (5–12) and retained most of its activity. At pH 4 it retained ~50% of its activity while pH 13 almost completely deactivated ML-005. (D) ML-005 showed halotolerance when incubated in increasing NaCl concentrations. After 7 days of incubation at close to saturated NaCl solution (5M), ML-005 still retained most of its activity.

Figure 6

(A) Metal ions showed negligible effect on ML-005 at a concentration of 1 mM, with copper showing the most drastic effect by inhibiting ML-005 by ~50%. (B) Organic solvents had an overall inhibiting effect on ML-005 without exception, but ML-005 was moderately stable in the presence of even 10% Methanol. (C) All inhibitors showed moderate inhibiting effect at a concentration of 1 mM, with relative activity staying at around 80%. Only PMSF showed almost complete inhibition of ML-005, consistent with an active-site serine. (D) Detergents at 1% were also found to have an overall inhibiting effect. CHAPS showed the least effect with 66% relative activity and SDS inactivating ML-005 completely with negligible remaining activity.