tRNA(Glu) mediated delta-aminolevulinate biosynthesis and biotechnology

delta-Aminolevulinate is the first universal committed intermediate for the biosynthesis of tetrapyrrole molecules functioning in respiration, photosy nthesis and as cofactors in other important enzyme reactions. There are two ways for the biosynthesis of delta-aminolevulinate. In one, a single enzym e condenses succinyl-CoA and glycine to produce delta-aminolevulinate. In t he other route glutamate is converted into delta-aminolevulinate with the h elp of three enzymes via glutamyl- tRNA(Glu). Aminoacylated tRNAs are ordin arily used for protein biosynthesis where they serve as substrates in the t ransfer of amino acids to develop the polypeptide chains following the codo ns of a given mRNA. In delta-aminolevulinate synthesis, glutamyl tRNA(Glu) is reduced to glutamate 1-semialdehyde and this is the only known example o f a reduction of an aminoacylated tRNA to an alpha-aminoaldehyde. The genes encoding the tRNA(Glu) and the enzymes as well as catalytically active rec ombinant enzymes are now available. Several aspects of utilising the tRNA(G lu) mediated delta-aminolevulinate biosynthetic pathway in industry and agr iculture are considered.