BENCE JONES PROTIEN

BENCE JONES

BENCE JONES PROTIEN.:- Bence-Jones protein Bence-Jones protein is an abnormal, low molecular weight protein, which is found in the urine of patients suffering from the malignant disease known as multiple myeloma

. A distinguishing property of Bence-Jones protein is that, at a temperature of between 40° and 60°C, the protein is precipitated. Other proteins precipitate between 60° and 70°C. At boiling point, Bence-Jones protein will redissolve, while other proteins will not. Again, on cooling to 60°C, the Bence-Jones proteins reappear. This protein is not well detected by reagent strips, but gives a positive reaction with sulphosalicylic acid.

 Method - Place about 5 ml of clear urine into each of three tubes. Add one drop of 5% acetic acid to one tube and two drops to the second tube. Place the tubes in a beaker of water with a thermometer inserted into one of the test tubes. Heat the beaker with a gentle flame. If Bence-Jones protein is present, a precipitate will appear between 40° and 60°C. At 100°C the precipitate will redissolve and disappear.

-Frequently, other proteins are present and will give positive result if present in considerable amounts. To confirm that the precipitate is due to Bence-Jones protein, filter the heated urine while still hot, and retest the filtrate. Alternatively, dilute the urine with distilled water and retest. While other proteins will disappear, true Bence-Jones protein remains positive.