Catalysis of the endolytic cleavage of beta-1,4-galactosaminic bonds between N-acetylgalactosamine and either D-glucuronic acid or L-iduronic acid to produce a mixture of Delta4-unsaturated oligosaccharides of different sizes that are ultimately degraded to Delta4-unsaturated tetra- and disaccharides.
Source:EC:4.2.2.20