Metabolism of chondroitinsulphate in the epiphyseal plate of puppies

• 1.

  1. The infrared spectra of partially purified acid mucopolysaccharide preparations from epiphyseal plate showed bands characteristic of chondroitinsulphate C as well as A, though no sharp chromatographic separation of the two was obtained.

• 2.

  2. Chromatography of unfractionated epiphyseal-plate extracts showed the presence of two protein peaks whose position in the elution pattern roughly coincided with two chondroitinsulphate peaks.

• 3.

  3. The rates of metabolism of the mixed chondroitinsulphates of various tissue extracts have been compared by the use of radioactive sulphate. The epiphyseal-plate chondroitinsulphate was metabolished at a much faster rate than from ribs. The chondroitinsulphate extractable only with alkali was distinguished from that extractable with water by a lower rate of metabolism, particularly evident in the extract of the epiphyseal-metaphyseal junction, and by the infrared spectrum, which indicates that it has a lower content of chondroitinsulphate C.

• 4.

  4. Chromatography of aqueous epiphyseal-plate extracts obtained at various times after injection of Na₂³⁵SO₄ demonstrated the depolymerisation in vivo of chondroitinsulphate, mainly prior to desulphation.