Improved assay and mechanism of the reaction catalyzed by the chitin synthase from Saccharomyces cerevisiae.

1. An improved filtration method is introduced to perform kinetic investigations on the chitin synthase reaction. This method is especially suited for the assay of a large number of samples necessary in enzyme kinetic studies. 2. From initial rate data the possibility could be excluded that the two-substrate reactions occurs by a random or a ping-pong mechanism. 3. Investigations of product inhibition exclude a rapid random mechanism but favour an ordered mechanism with UDP-N-acetylglucosamine as the first substrate. 4. This result was confirmed by isotope exchange studies.