ISSN:
1573-5028
Keywords:
Catharanthus roseus
;
cell culture
;
tryptophan decarboxylase
;
enzyme induction
;
purification
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The purification of tryptophan decarboxylase from Catharanthus roseus (TDC, E.C.:4.1.1.27), to apparent homogeneity, is described. The enzyme represents a soluble protein with a molecular weight of 115 000±3 000, consisting of 2 identical subunits of 54 000±1 000. The pI was estimated to be 5.9 and the Km for L-tryptophan was found to be 7.5×10-5 M. Phenylalanine, tyrosine and DOPA were not decarboxylated by tryptophan decarboxylase from Catharanthus cells. Similar to the aromatic amino acid decarboxylase from hog kidney the enzyme does not appear to be obligatorily dependent on exogenously supplied pyridoxal phosphate, as it seems to contain a certain amount of this cofactor. The average percentage of TDC in the cells was found to be 0.002% in the growth medium while the level increased up to 0.03% when indole alkaloid biosynthesis was induced. The role of the protein as a bottleneck enzyme of indole alkaloid biosynthesis is discussed.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00017782
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