Sepharose CL-2B chromatography of PGs in extracts from normal and DSLD-affected tendons. Guanidium HCl extracts from midmetacarpal portions of SDFTs from 2 affected horses (no. 20 and 21, Table 1) and from one control horse (no. 1, Table 3) were separated on a molecular sieve Sepharose CL-2B column (1.3 × 110 cm, equilibrated and eluted in 4 M guanidine HCl) at 0.1 ml/min. The majority of PGs eluted in one wide peak (fractions 66–81).