Purification and characterization of three toxins and two agglutinins from Abrus precatorius seed by using lactamyl-Sepharose affinity chromatography.

Three toxins, abrin-I, -II, and -III, and two agglutinins, APA-I and -II, were purified from the seeds of Abrus precatorius by lactamyl-Sepharose affinity chromatography followed by gel filtration and DEAE-Sephacel column chromatography. Abrin-I did not bind on DEAE-Sephacel column chromatography and the bound abrin-II, abrin-III, APA-I, and APA-II were eluted with a sodium acetate gradient. The identity of each protein was established by sodium dodecylsulfate-polyacrylamide gel electrophoresis and isoelectric focusing.

Microbial production of L-tryptophan: a review.

Microbial production of L-tryptophan has been reviewed with 172 references. The review includes different tryptophan producing microorganisms, their optimal cultural conditions, yields, assay and process of recovery. It also includes a discussion on the pathway of tryptophan biosynthesis and its regulation.

L-phenylalanine production by double auxotrophic mutants of Arthrobacter globiformis.

A number of tryptophan-plus-tyrosine double auxotrophs have been isolated from a glutamate producing Arthrobacter globiformis excreting L-phenylalanine by two-step mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. For the three potent mutants tested the medium of Alföldi was found to be the best. The optimum tryptophan, tyrosine and biotin concentrations for phenylalanine production of these mutants were 0.

Microbial production of L-phenylalanine: a review.

Microbial production of L-phenylalanine by direct fermentation and by substrate conversion has been reviewed. The review also includes a discussion on different other methods for phenylalanine production, their advantages and disadvantages with mutants and genetically tailored strains. Biosynthesis of phenylalanine, its regulation in hyperproducing strains and recovery of phenylalanine has been discussed in brief.