Cystathionine β-lyase, Recombinant Microorganisms

Cystathionine β-lyase (25 nM; 10 min) catalyzes L-(+)-cystathionine (100 μM) to homocysteine. Cystathionine β-lyase activity can be measured by monitoring the formation of homocysteine at 412 nm, using 5,5′-dithio-bis-(2-nitrobenzoic acid) as a detector of free thiol^[1].
Product Information
This product is derived from recombinant microorganisms, with a molecular weight of 54 kda and a km value of 1.6 ×10^-3 M (L-Cystathionine). It is stable in the pH range of 6.0-10.0 (25°C, 16 h), with an optimal pH of 8.0. It contains stabilizers Triton X-100 and glycerol, and can be used for the research and development and large-scale preparation of homocysteine reagents.

Activity assay method
1. Reagent preparation
1) Reagent 1: In 100 mM pH 8.0 Tris-HCl buffer, add DL-cystathionine to a final concentration of 3.5 mM, NADH to a final concentration of 0.15 mM, pyridoxal phosphate to a final concentration of 0.05 mM, and LDH to a final concentration of 10 U/mL.
2) Reagent 2: 50 mM pH 8.0 Tris-HCl buffer.
3) Enzyme solution: Dilute the enzyme solution to 0.8-2.4 U/mL with reagent 2.

2. Operation steps
1) Add 1 mL of reagent 1 to a 1 mL cuvette and incubate in a 37°C water bath for 5 min.
2) Add 20 μL of the sample to be tested and mix well.
3) React at 37°C and measure the absorbance change ΔAs within 1 min at 340 nm.
*Replace the sample to be tested with reagent 2. The other steps are the same. Measure the absorbance change ΔAb within 1 min.
ΔA=ΔAs - ΔAb
3. Activity calculation
1.02: Total volume of reaction solution (mL);
0.02: Enzyme solution volume (mL);
1.0: Light path length (cm);
df: Dilution factor;
C: Enzyme concentration (mg/mL);
6.22: Millimolar absorbance coefficient (cm²/μmol) of the chromophore at 340 nm under standard reaction conditions.

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.