L-Arginine serves as a common substrate for both nitric oxide synthase (NOS) and arginase in the cell. NOS catalyzes the oxidation of arginine to citrulline and NO with Nω-hydroxy-L-arginine (NOHA) formed as an intermediate. Arginase, on the other hand, catalyzes the hydrolysis of arginine into urea and L-ornithine. Thioarginine (hydrobromide) is a colorimetric substrate for arginase that provides the basis for continuous spectrophotometric measurement of enzyme activity.1 It exhibits Km and kcat values of 0.5 mM and 18,000 min−1, respectively, which are similar to physiological substrate arginine.1 The thiol product of the reaction reacts with DTNB to produce 2-nitro-5-thiobenzoate for easy visualization at 405-420 nm.
1
Han, S.H., and Viola, R.E. A spectrophotometric assay of arginase. Anal Biochem295117-119(2001).
Formal Name
5-[(aminoiminomethyl)thio]-L-norvaline
Molecular Formula
C6H13N3O2S · HBr
Formula Weight
272.2
Formulation
A crystalline solid
Purity
>95%
Stability
2 years
Storage
-20°C
Shipping
Room temperature
in continental US; may vary elsewhere
SMILES
Copy SMILES to clipboard
N/C(SCCC[C@H](N)C(O)=O)=N/[H].Br
Background Reading
Han, S.H., and Viola, R.E. A spectrophotometric assay of arginase. Anal Biochem295117-119(2001).
Thioarginine (hydrobromide) is available in the following screening
library: