The rate of ammonia liberation from [image] NaOH solns. at lOOt containing heparin, chondroitinsulfuric acid, and glucosamine was detd. Heparin, shown to have a sulfamic acid residue-NHSO2OH, which is resistant to alkali, liberated only 10% of its N in 135 min. Chondroitinsulfuric acid, having an acetyl amino group that is easily susceptible to alkali, liberated 55% of its total N as ammonia in 135 min., as compared with 90% for glucosamine. This evidence gives further support to sulfamic acid structure for heparin.