Heterologous Expression in Microorganisms

Heterologous expression of individual cDNAs in Escherichia coli followed by enzyme assays in the presence of putative substrates have been used extensively for characterization of plant P450s , for example, for the CYP79s involved in 

Cinnamic acid 4-hydroxylase from Helianthus tuberosus (Jerusalem artichoke) was the first plant P450 to be functionally characterized. CYP73A1 was designated as the first member of the CYP73 family. This cDNA was isolated from an expression library using antibodies raised against the isolated P450 protein (Section 3.5). Cinnamic acid 

4-hydroxyIase catalyzes an essential step in the phenylpropanoid pathway and it is considered to be ubiquitous in plants (see Section 3.1). 

Cinnamate 4-hydroxylases catalyze the hydroxylation of frans-cinnamic acid into trans-p-coumaric acid. The ability to monitor this enzyme activity in Jerusalem artichoke allowed isolation of the P450 enzyme CYP73A1 using conventional chromatography and generation of specific antibodies .  

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