The effects of trypsin treatment on proteoglycan biosynthesis by bovine articular cartilage

Abstract

The effects of mild or severe trypsin treatment of bovine articular-cartilage slices in tissue culture were studied by monitoring the incorporation of [35S]sulphate into proteoglycans. Moderate trypsin treatment caused a subsequent marked inhibition of proteoglycan biosynthesis, which was reversible with time. Analysis on Sepharose CL-2B of the proteoglycan species synthesized showed that, directly after trypsin treatment, there was a 30% increase in the synthesis of the low-M(r) proteoglycan (K(av.) 0.71), and the total decrease in proteoglycan biosynthesis was reflected in a decrease in the synthesis of the high-M(r) proteoglycan species (K(av.) 0.31). The small proteoglycan was partially characterized and shown to be a true biosynthetic product and not a breakdown product. Trypsin treatment (20 μg/ml per 100 mg of tissue) of cartilage slices also resulted in an increase in the glycosaminoglycan chain slice of the large proteoglycan, but not of the small proteoglycan.