The microbial degradation of quinolizidine alkaloids

A strain of Pseudomonas putida capable of growing on lupanine as its sole source of carbon and nitrogen has been isolated. Lupanine is a plant-produced quinolizidine alkaloid containing fused N-heterocyclic rings and little is known about the degradation of this type of structure. The first reaction in the breakdown pathway has been established but further steps are proving difficult to identify. The enzyme catalysing this first step has been well studied and its gene sequenced. Degradative genes are often part of an operon or are clustered in the genome and the purpose of sequencing the genome of the organism is to see if this first gene is part of such an operon and to try to identify neighbouring genes. This should give clues as to enzymes involved in the further steps in the degradative pathway.