Biosynthesis of opiate alkaloids

An expression vector comprising a nucleotide molecule selected from the group consisting of:

• i) the nucleotide sequence shown in SEQ ID NO:
• 7, 8, 9 or 10;
• ii) a nucleotide sequence degenerate to the nucleotide sequence defined in (i) as a result of the genetic code;
• iii) a nucleotide sequence, the complementary strand of which hybridizes under stringent hybridization conditions to the nucleotide sequence shown in SEQ ID NO:
• 7, 8, 9 or 10, wherein said nucleic acid molecule encodes a polypeptide involved in the biosynthesis of P. somniferum opiate alkaloids or intermediates in the biosynthesis of opiate alkaloids;
• iv) a nucleotide sequence that encodes a polypeptide comprising the amino acid sequence shown in SEQ ID NO:
• 17, 18, 19 or 20;
• and
• v) a nucleotide sequence that encodes a polypeptide comprising an amino acid sequence, wherein said amino acid sequence is modified by addition, deletion or substitution of at least one amino acid residue as represented in iv) above and which has retained or enhanced opiate alkaloid biosynthetic activity.