Characterization and Histochemical Localization of Nonspecific Esterase from Ascocarps of Desert Truffle (Terfezia claveryi Chatin)

Abstract

An esterase activity from Terfezia claveryi Chatin ascocarps, a mycorrhizal hypogeous fungus, is described for the first time. The enzyme was partially purified using phase partitioning in Triton X-114 (TX-114), achieving a reduction of 87% in the triglyceride content and the removal of 63% of phenols. The enzyme showed maximum activity toward short-chain p-nitrophenyl esters, and no interfacial activation was observed, indicating that the enzyme responsible for this activity is an esterase and not a lipase. This esterase presented its maximum activity at pH 7.4 and 60 degrees C. The values obtained for Km at pH 7.4 were 0.3 mM for p-nitrophenyl butyrate and 0.6 mM for p-nitrophenyl acetate with catalytic efficiencies (Vmax/Km) of 0.23 and 0.32, respectively. T. claveryi esterase was inhibited by phenylboric acid, indicating that serine residues were involved in the enzyme activity. This activity was localized only in the hypothecium and was absent from the peridium and gleba.

PARTIAL PURIFICATION AND CHARACTERIZATION OF A CALCIUM‐DEPENDENT ALKALINE PHOSPHATASE FROM THE CYANOBACTERIUM ARTHROSPIRA PLATENSIS 1

“…This characteristic is useful for removing hydrophobic proteins and compounds such as phenols, chls, and lipids (Sánchez‐Ferrer et al. 1994, Pérez‐Gilabert et al. 2001, 2005a,b, 2010), which partition to the detergent‐rich phase.…”

“…With the second phase partitioning (2nd TX‐114 row in Table 1), a slight increase in the specific activity was obtained and the chl present in the crude extract was completely removed. The purification yield obtained in this assay is characteristic of phase partitioning with TX‐114 (Pérez‐Gilabert et al. 2005a,b).…”

“…Although TX-114 and TX-100 have a similar capacity to digest membranes, a solution of TX-114 is turbid at room temperature and separates into two phases at $35°C because of the formation of large micellar aggregates (Sánchez-Ferrer et al 1994). This characteristic is useful for removing hydrophobic proteins and compounds such as phenols, chls, and lipids (Sánchez-Ferrer et al 1994, Pérez-Gilabert et al 2001, 2005a,b, 2010, which partition to the detergent-rich phase. In the present article, TX-114 was used both to release the enzyme from the pellet and, after phase partitioning, to remove chls and other pigments (a representative purification is presented in Table 1).…”

Partial purification, characterisation and histochemical localisation of alkaline phosphatase from ascocarps of the edible desert truffleTerfezia claveryiChatin

“…Most studies of desert truffles have been morphological or bromatological, but few biochemical investigations have been performed (Pérez‐Gilabert et al. 2001, 2004, 2005).…”

“…Most studies of desert truffles have been morphological or bromatological, but few biochemical investigations have been performed (Pérez-Gilabert et al 2001, 2004, 2005. Our group took Terfezia claveryi-Helianthemum almeriense as a model system to study the process of mycorrhization (Morte et al 1994Gutiérrez et al 2003).…”