Stimulatory Effect of Phenylmethylsulfonyl Fluoride upon Sulfate Uptake by Costal Cartilage

Abstract

Uptake of [35Slsulfate by segments of rat costal cartilage during culture was greatly stimulated when freshly prepared phenylmethylsulfonyl fluoride or diisopropylfluorophosphate was included in the incubation medium. By contrast, hydrolysed diisopropylfluorophosphate, sodium fluoride or soybean trypsin inhibitor did not stimulate [35Slsulfate uptake. Incorporation of four other radioactive precursors of cartilage synthesis was almost completely suppressed during cartilage incubation in the presence of phenylmethylsulfonyl fluoride. However, stimulation of [3SSlsulfate binding by the latter was shown to occur at sites other than on glycosaminoglycan molecules and to a similar degree with both active and inactivated cartilage. These and other data indicate that the stimulatory effect of phenylmethylsulfonyl fluoride on [3sSlsulfate uptake is independent of normal metabolic processes, and may involve the binding of phenylmethylsulfonyl fluoride to cartilage proteins.