Display omitted The serum fraction of latex from Hevea brasiliensis, the para rubber tree, is known to contain an endo-chitinolytic enzyme, hevamine. Herein the activity of the rubber serum towards β-chitin is investigated. The serum contained 6 mg/mL of protein and a chitinolytic activity of 18 mU per mg of protein. The optimum ratio of enzyme to chitin was 0.22 mU/mg, and the optimum substrate concentration was 60 mg/mL. The optimum pH range was pH 2–4, and the optimum temperature was 45 °C. At these conditions both (GlcNAc) 2 and GlcNAc were produced in a molar ratio of approximately 2:1. The hydrolysis of 300 mg of chitin with 64 mU of the rubber serum for 8 days under the optimum conditions gave 39 mg of GlcNAc and 108 mg of (GlcNAc) 2 as determined by HPLC. Mixing the rubber serum preparation with an Aspergillus niger pectinase preparation containing β- N-acetylhexosaminidase can be used to produce almost exclusively the GlcNAc monomer in about 50% yield.