Special publicationfn1fn1Papers with this heading have received accelerated publication, due to their particular significance in the field of phytochemistry. Purification and characterization of acetyl coenzyme a: 10-hydroxytaxane O-acetyltransferase from cell suspension cultures of Taxus chinensis

1999 ◽  
Vol 50 (5) ◽  
pp. 763-774 ◽  
Author(s):  
Birgitta Menhard ◽  
Meinhart H Zenk
Keyword(s):  
Cell Suspension ◽  
Coenzyme A ◽  
Cell Suspension Cultures ◽  
Suspension Cultures ◽  
Taxus Chinensis ◽  
Purification And Characterization ◽  
Acetyl Coenzyme A ◽  
Acetyl Coenzyme

Partial Purification and Characterization of S-Adenosyl-ʟ-Methionine: Norreticuline N-Methyltransferases from Berberis Cell Suspension Cultures

1986 ◽  
Vol 41 (1-2) ◽  
pp. 126-134 ◽  
Author(s):  
Chi-Kit Wat ◽  
Paul Steffens ◽  
Meinhart H. Zenk
Keyword(s):  
Cell Suspension ◽  
Cell Suspension Cultures ◽  
Apparent Molecular Weight ◽  
Suspension Cultures ◽  
Partial Purification ◽  
Enzymatic System ◽  
Purification And Characterization ◽  
Temperature Optimum ◽  
Ph Optimum

Abstract Two new N-methyltransferases (NMT-I and NMT-II) were found to occur in Berberis vulgaris cell suspension cultures. One of these enzymes (NMT-I) was partially purified (100-fold) and characterized. This enzyme is specific for tetrahydrobenzylisoquinoline alkaloids and S-adenosyl-ʟ-methionine serves as the methyl donor. The apparent molecular weight of the enzyme is 68,000. The pH optimum of the enzyme is 7.6, the temperature optimum 35 °C. Apparent KM values for (R)-tetrahydropapaverin as substrate were 0.2 mᴍ and for SAM 0.04 mᴍ. The preparation of the same type of enzyme from B. wilsoniae var. subcaulialata was utilized as an efficient enzymatic system for the synthesis of stereochemically pure (R)-as well as (S)-reticuline labelled with tritium or 14C at the N-CH3 group. Enzymes catalyzing this type of reactions are named S-adenosyl-ʟ-methionine: norreticuline N-methyltransferases.

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