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Mannitol Biosynthesis in Pyrenochaeta terrestris II. D‐Mannitol‐l‐phosphatase
Author(s) -
Aitken W. Brent,
Wright James R.,
Letourneau Duane
Publication year - 1969
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1969.tb07428.x
Subject(s) - mannitol , sephadex , chemistry , enzyme , phosphatase , phosphate , hydrolysis , biochemistry , tris , enzyme assay , chromatography
Cell‐free extracts of mycelial mats of Pyrenochaeta terrestris contained an enzyme which hydrolyzed mannitol‐l‐phosphate to mannitol and inorganic phosphate. Greatest mannitol‐1‐phosphatase activity occurred early in the growth period when the mannitol content of the mats was at a maximum. The enzyme was active over a broad pH range with optimum activity between pH 6.5–7.0 in 0.05 M Tris‐maleate buffer. Maiinitnl‐1‐phosphatase was inhibited by reagents known to inhibit enzymes containing ‐SH groups. A 10‐fold purification was attained by a combination of (NII 4 ) 2 SO 4 fractionation and gel filtration on Sephadex G‐100. The partially purified enzyme required Mg −2 for activity and did not hydrolyze a number of sugar phosphates. Km values for mannitol‐l‐phosphate and Mg −2 with the partially purified extract were 3 × 10 −3 M and 1 × 10 −4 M respectively.