Open AccessStudies on Lichen Enzymes
Author(s) -
Schultz Joachim,
Mosbach Klaus
Publication year - 1971
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1971.tb01526.x
Subject(s) - esterase , enzyme , chemistry , hydrolysis , hydrolase , substrate (aquarium) , benzoic acid , polyacrylamide gel electrophoresis , carboxylesterase , biochemistry , chromatography , enzyme assay , serine , serine hydrolase , polyacrylamide , monomer , organic chemistry , biology , polymer chemistry , ecology , polymer
From the lichen Lasallia pustulata a new enzyme, “orsellinate depside hydrolase”, capable of catalyzing the hydrolysis of certain depsides to corresponding resorcylic acid monomers, has been isolated. The enzyme is extremely substrate‐specific; only depsides based on orsellinic acid (2,4‐di‐hydroxy‐6‐methyl‐benzoic acid) alone are acceptable. Phenyl benzoate and m ‐digallic acid are not hydrolysed. Purification of the enzyme 135‐fold has been achieved with a final specific activity of 1300 U/mg of protein. The enzyme has a molecular weight of 42000 as determined by dodecylsulphate‐polyacrylamide gel electrophoresis. Only a single sharp peak was obtained by analytical ultracentrifugation. Electrofocussing of the hydrolase in polyacrylamide gel resolved the protein into four distinct enzymatically‐active bands. A K m of 56 μM has been determined using the depside lecanoric acid as substrate. The enzyme has been shown to be unusually stable to heat. On treatment of the enzyme for 22 h with 5 mM diisopropylfluorophosphate 75% of the activity was lost, typical of a serine esterase. A spectrophotometric method suitable for the assay of orsellinate depside hydrolase is described.