1003605-41-1Relevant academic research and scientific papers
A simple chemical method for synthesizing malonyl hemiesters of 21-hydroxypregnanes, potential intermediates in cardenolide biosynthesis
Padua, Rodrigo M.,Waibel, Reiner,Kuate, Serge Philibert,Schebitz, Pia K.,Hahn, Stefanie,Gmeiner, Peter,Kreis, Wolfgang
, p. 458 - 465 (2008)
A simple and versatile method for the chemical synthesis of 21-hydroxypregnane 21-O-malonyl hemiesters which may be important intermediates of cardenolide biosynthesis is described. Starting from commercial β-methyldigitoxin, acid hydrolysis followed by 3β-O-acetylation and ozonolysis with reductive cleavage of the ozonides afforded 3β-acetoxy-5β-pregnane-14β,21-diol-20-one which was finally converted into the target compound by treatment with malonyl chloride. The malonylation protocol was optimized using deoxycorticosterone (DOC) as the pregnane educt.
Purification and characterization of malonyl-coenzyme A: 21-hydroxypregnane 21-O-malonyltransferase (Dp21MaT) from leaves of Digitalis purpurea L.
Kuate, Serge Philibert,Padua, Rodrigo M.,Eisenbeiss, Wilhelm F.,Kreis, Wolfgang
, p. 619 - 626 (2008)
With respect to the cardenolide pathway and the characterization of enzymes involved in the formation of cardenolides, a malonyltransferase, termed malonyl-coenzyme A: 21-hydroxypregnane 21-O-malonyltransferase (Dp21MaT) has been purified. The enzyme catalyses the transfer of the malonyl moiety from malonyl-coenzyme A to 21-hydroxypregnane substrates. Malonyltransferase activity was checked in several potential starting materials including fresh leaves and cell suspension cultures from different plants. Fresh Digitalis purpurea L. leaves turned out to be the best enzyme source. The purification protocol included ammonium sulphate precipitation, hydrophobic interaction chromatography on Phenylsepharose 6 FF, ion exchange chromatography on Source 30 Q, affinity chromatography on Cibacron Blue 3GA and gel filtration on Superdex 75. Gel filtration and native SDS-PAGE analysis showed that Dp21MaT exists as a monomer with a molecular mass of 27 kDa. Its pI, as determined by isoelectric focusing, was 4.66. The enzyme showed maximal activity at pH 6.5 when incubated at 42 °C. The energy of activation was 29.28 kJ mol-1, whereas that of inactivation was 48.57 kJ mol-1. Dp21MaT was purified 252-fold with a yield of about 1%. Hanes plots of kinetic data indicated Km values of 99 μM (Vmax 47.57 μkat kg-1) and 28.44 μM (Vmax 39.4 μkat kg-1 protein) for 3β-benzoyloxy-5β-pregnane-14β,21-dihydroxy-20-one and malonyl-CoA, respectively.
