39508-55-9

Upstream product

• 98-88-4 benzoyl chloride 
• 134-81-6 benzil 

Downstream Products

• 57230-45-2 <3-(3)H>-trans-cinnamic acid 
• 31262-72-3 [(3R)-³H]-L-phenylalanine 
• 34100-63-5 (3R)-[3-3H]-L-tyrosine 

Relevant academic research and scientific papers

Elusive transition state of alcohol dehydrogenase unveiled

For several decades the hydride transfer catalyzed by alcohol dehydrogenase has been difficult to understand. Here we add to the large corpus of anomalous and paradoxical data collected for this reaction by measuring a normal (>1) 2° kinetic isotope effect (KIE) for the reduction of benzaldehyde. Because the relevant equilibrium effect is inverse (a comprehensive model for the tunneling ready state (TRS) of the reaction that fits into the general scheme of Marcus-like models of hydrogen tunneling. The TRS is the ensemble of states along the intricate reorganization coordinate, where H tunneling between the donor and acceptor occurs (the crossing point in Marcus theory). It is comparable to the effective transition state implied by ensemble-averaged variational transition state theory. Properties of the TRS are approximated as an average of the individual properties of the donor and acceptor states. The model is consistent with experimental findings that previously appeared contradictory; specifically, it resolves the long-standing ambiguity regarding the location of the TRS (aldehyde-like vs. alcohol-like). The new picture of the TRS for this reaction identifies the principal components of the collective reaction coordinate and the average structure of the saddle point along that coordinate.

Kinetic and solvent isotope effects on biotransformation of aromatic amino acids and their derivatives

Aromatic amino acids such as l-phenylalanine, l-tryptophan, 3′,4′-dihydroxy-l-phenylalanine (l-DOPA), and their derivatives 3′,4′-dihydroxyphenylacelaldehyde (DOPAL) and 3′,4′-dihydroxyphenylethanol (DOPET), play an essential role in human metabolic processes. Incorrect or slow biotransformation of these compounds leads to some metabolic dysfunctions and in some cases to some neurodegenerative diseases. Therefore, studies of the biotransformation mechanisms of these metabolites draw biochemists' and medical researchers' attention. This study investigates the mechanisms of biotransformation of the aforementioned compounds using kinetic (KIE) and solvent (SIE) isotope effect methods. The overview presents the results and the numerical values of KIE and SIE methods, obtained in the study of biotransformation of l-phenylalanine, 5′-chloro-l-tryptophan, and l-DOPA, catalyzed by the enzymes from the lyases group (phenylalanine ammonia lyase, tryptophan indole-lyase, and tyrosine decarboxylase). Deuterium KIE was also determined during the deamination of 2′-chloro-l-phenylalanine in the presence of the enzyme l-phenylalanine dehydrogenase, as well as in the conversion of DOPAL into DOPET catalyzed by the enzyme alcohol dehydrogenase. The values of KIE and SIE have been determined using a noncompetitive spectrophotometric and a competitive (combined with internal radioactivity standard) radiometric methods.

Synthesis of tritium labeled [3R-3H]-, and [3S-3H]-L-phenylalanine

The synthesis of two selectively labeled isotopomers of L-phenylalanine, (Phe), using chemical and enzymatic methods is reported. The [3R-3H]-L-Phe isotopomer has been obtained from [3-3H]cinnamic acid prepared from benzaldehyde and malonic acid using tritiated water as a source of radioactive label, and by addition of ammonia in the presence of enzyme PAL. The [3S-3H]-L-Phe isotopomer has been synthesized by addition of ammonia to cinnamic acid in a buffered medium containing PAL and tritiated water.