ISO Recombinant Carboxypeptidase B Solution Under -20℃ And Repeated Freezing-Thawing , Specific Activity ≥170 u

Stability of RCPB solution under -20℃ and repeated freezing-thawing

ISO Recombinant Carboxypeptidase B Solution Under -20℃ And Repeated Freezing-Thawing , Specific Activity ≥170 u

Recombinant Carboxypeptidase B

REAGENT

1) Reagent A. 25 mM Tris-HCl Buffer with 100 mM Sodium Chloride, pH 7.65 at 25°C±0.5°C. (Prepare 100 ml in deionized water using Tris Hydrochloride, and Sodium Chloride. Adjust to pH 7.65 at 25°C with 1 M NaOH or 1M HCl.)

2) 1.0 mM Hippuryl-L-Arginine Solution (Hippuryl-L-Arg)

Weight 16.7 mg Hippuryl-L-Arginine (Sigma Prod. No. H-2508), dissolve in 50 ml Reagent A to obtain 1.0 mM (Hippuryl-L-Arg). PREPARE FRESH.).

3) RCPB Solution

Three batches RCPB lyophilized powder (RC110919, RC110106 and RC110304), prepare 10 mg/ml with reagent A, respectively, and separated into 30 tubes for each batch, stored under -20℃.

METHOD:

Long term stability of RCPB solution: The initial activity was measure just after preparation and taken as 100%. The activity was measure every 2 months, 3 parallel samples for each batch each time, take average, calculate residual rate of activity compared with initial one and then draw a stability curve.

Stability of RCPB solution during 10 cycles repeated freezing and thawing:The initial activity was measure just after preparation and taken as 100%. The activity of 3 samples of three batches were measured according SOP just after taking from -20℃ and thawing in room temperature. Repeated 10 times. Calculate residual rate of activity compared with initial one and then draw a stability curve.

CONCLUSION:

RCPB solution (10mg/ml) is stable when kept under -20℃ in 1 year.

RCPB solution (10mg/ml) is stable during 10 cycles repeated freezing and thawing.

Fig 1. Long term stability of RCPB solution (10mg/ml) for 12 months kept under -20℃

Fig 2. Stability of RCPB solution (10mg/ml) during 10 cycles repeated freezing and thawing