Tryptophan synthase beta 1

Beta replacement is catalyzed by such enzymes of amino acid biosynthesis as tryptophan synthase (Chapter 25),184 O-acetylserine sulfhydrylase (cysteine synthase),185 186a and cystathionine (3-synthase (Chapter 24).187 188c In both elimination and (3 replacement an unsaturated Schiff base, usually of aminoacrylate or aminocrotonate, is a probable intermediate (Eq. 14-29). Conversion to the final products is usually assumed to be via hydrolysis to free aminoacrylate, tautomerization to an imino acid, and hydrolysis of the latter, e.g., to pyruvate and ammonium ion (Eq. 14-29). However, the observed stereospecific addition of a... 

An example of enzyme induction is the growth of the bacteria Escherichia eoli in a suitable culture medium. If no beta-galactoside is added to the medium, the bacteria Form scarcely any of the enzyme that hydrolyzes that sugar. The addition of the sugar to the medium increases the production of the enzyme by the cell by as much as 10.000 times. On the other hand, the same bacteria will produce the enzyme tryptophan synthase only if tryptophan is absent from the culture medium. These observations are useful, not oniy... 

Beta replacement is catalyzed by such enzymes of amino acid bios5mthesis as tryptophan synthase (Chapter 25), O-acetylserine sulfhydrylase (cysteine synihase), and cystathionine 3-synthase (Chapter In both elimination and (I replace-... 

Hyde, C. C., Ahmed, S. A., Padlan, E. A., Miles, E. W. and Davies, D. R. 1988, Three-dimensional structure of the tryptophan synthase alpha 2 beta 2 multienzyme complex from Salmonella typhimurium. Journal of Biological Chemistry 263, 17857-17871. 

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