Characteristics of proteoglycans isolated from small and large bovine ovarian follicles

Acetone precipitates of bovine follicular fluid from small (3-5 mm) and large (10-20 mm) follicles were fractionated by nondissociative procedures involving chromatography on Sephacryl S-300, DEAE cellulose, and Sepharose CL-2B. Most of the proteoglycan material eluted with a relatively low molecular weight (Kav = approximately 0.6) from Sepharose CL-2B. Comparisons of the proteoglycans from small versus large follicles showed respective differences of 20 versus 34% protein, 74 versus 48% chondroitin sulfate-B, and 4 versus 8% other sugars. The protein moiety of the proteoglycan from small follicles exhibited greater proportions of aspartic acid, serine and glycine, but lower proportions of theonine, alanine and valine, than its analog from large follicles. Chromatography on Sepharose CL-2B in 4 M guanidine-HCl failed to alter the elution position of the proteoglycans. However, noticeable decreases occurred in the protein and total amino acid content of the proteoglycans, especially from large follicles, suggesting preparations obtained from the nondissociative procedures contained aggregates of peptides, glycosaminoglycans, and/or proteoglycan fragments. Proteoglycans from both sizes of follicles were enriched in serine, glutamic acid and glycine, but diminished in leucine and lysine following the dissociative gel filtration. Differences in composition of the proteoglycans may be related to follicular differentiation.