Those originally employed were based either on the fusion of the PCE to a tumour specific antibody (Antibody-Directed Prodrug Therapy, ADEPT) or on the delivery of the gene encoding the PCE using viral or non-viral vectors (Gene-Directed Enzyme Prodrug Therapy, GDEPT).
Urea is widely used in fertilizers as a source of nitrogen and is an important raw material for the chemical industry. Friedrich WÃ¶hler's discovery in 1828 that urea can be produced from inorganic starting materials was an important conceptual milestone in chemistry.
Here is a link to learn more. We make our own from unsalted organic butter (when it goes on sale, of course). As for the vegetables, itâs up to you. I like the combination of carrots, potatoes and onions but you can use whatever root vegetables like. Have fun with it. Use different colored potatoes or carrots as well as red and white onions.