I'm trying to obtain a better understanding of the Guthrie Test, which checks whether people have a disease called PKU. The Guthrie test uses bacteria to check for Phenylalanine (the amino acid) in blood samples. If both Phe and B-2-thienylalanine are available on the medium, the bacteria will grow. However, if only B-2-thienylalanine is available the bacteria will not grow.
In all of the articles I can find, I have seen no explanation, just a link to a paper that I can't find on the internet.: " A standard culture of Bacillus subtilis was incubated on agar in the presence of an antagonist of phenylalanine (B-2-thienylalanine), which prevents the bacteria from growing.3 " Link The reference they mention here is: "The inhibition assay: Its use in screening urinary specimens for metabolic differences associated with mental retardation" by R. Guthrie from 1960.
Do we know what mechanism this protein is inhibiting?
Any help would be greatly appreciated.