Uridine diphosphate glucose dehydrogenase in normal human synovial cells in culture

Extracts containing uridine diphosphate (UDP) glucose dehydrogenase (EC 1.1.1.22) activity were prepared from 5 normal human synovial cell lines and sources of variation in the method determined. The mean catalytic activity of UDP-glucose dehydrogenase from the 5 extracts was 12.0 +/- 2.4 x 10(-3) International Units/mg protein. The KmUDP-glucose was estimated as 3.90 +/- 1.56 x 10(-5) M and the KmNAD+ was estimated as 1.72 +/- 0.60 x 10(-4) M. Maximum catalytic activity occurred in a temperature range of 55 degrees C-68 degrees C and in a pH range of 8.1-8.4. The mechanistic implications of these data in the normal human diarthrodial joint are discussed.