Which precipitates at 50 to 60-degree C but disappears on heating?

Bence Jones protein is found typically in multiple myeloma. It can be identified in urine by its characteristic property of coagulation when heated to 50-degree C but redissolving at 70 degree C. Bence Jones proteins are the light chains of immunoglobulins and so may occur as the kappa or lambda forms. But in any one patient, the chain is either kappa or lambda only, and never both.