Hans de Beer

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A lipase from Rhizopus oryzae DSM 853 (ROL) was cloned from a chromosomal gene bank, sequenced and overexpressed in Escherichia coli. ROL and its precursors ProROL and PreProROL were purified and their pH and temperature profile was determined. In contrast to ROL, ProROL and PreProROL had considerably higher thermostability and a slightly higher pH optimum.(More)
The fungus Rhizopus oryzae synthesizes an extracellular lipase precursor bearing N-terminal pre- and pro-sequences. Our studies in Escherichia coli and using recombinant lipase in vitro indicate that the prosequence of 97 amino acids has at least two functions. First, it modulates the enzyme activity of the lipase so that this enzyme can initially be(More)
Both an active enzyme conformation and stabilization of tetrahedral transition states are essential for the catalysis of ester bond hydrolysis by lipases. X-ray structural data and results from site-directed mutagenesis experiments with proteases have been used as a basis for predictions of amino acid residues likely to have key functions in lipases. The(More)
Deterioration of archaeological material often occurs as a consequence of change in the water balance. To better understand the preservation conditions and to protect archaeological deposits, it is necessary for any archaeological site to be placed within its wider natural environment, to understand the natural hydrological balance and possible changes that(More)
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