The enzymic degradation of porphyran.

1. The algal galactan, porphyran, was incubated with enzymes from a Cytophaga sp. and the products were examined. 2. Only about 30% of the porphyran was recovered in the form of oligosaccharides, the remainder being of high molecular weight. 3. Among the saccharides were d-galactose, 6-O-methyl-d-galactose, neoagarobiose, neoagarotetraose and oligosaccharides containing 6-O-methyl-d-galactose, the principal of which has been tentatively identified as 6(3)-O-methyl-neoagarotetraose. Fragments containing sulphate were also isolated but not identified. 4. Within the alternating sequence of the d- and l-forms of derivatives of galactose in porphyran, 6-O-methyl-d-galactose replaces d-galactose in a random manner.