The axonal transport of DOPA‐decarboxylase (EC 184.108.40.206) was investigated in rabbit sciatic nerves by means of in vitro stop‐flow techniques. Enzyme activity accumulated just proximal to a region that was locally cooled to 5°C in nerves that were elsewhere incubated at 37°C. The accumulation of enzyme activity was linear with time and corresponded to an average orthograde transport velocity of 11 mm/day. Retrograde transport was not detected. When nerves that had been locally cooled for 3 h were rewarmed, the accumulated enzyme activity moved distally along them as a wave with a narrow range of velocities. The front of this wave traveled at a rate of about 150mm/day, and the mean velocity of the wave was about 120 mm/day. These values are much lower than those previously obtained for tyrosine hydroxylase (EC 220.127.116.11), dopamine‐β‐hydroxylase (EC 18.104.22.168) and norepinephrine in similarly designed experiments. Thus DOPA‐decarboxylase appeared to be transported at intermediate velocities, and, since the mean velocity of the moving fraction was about 11 times the average velocity, it is ljkely that only 9% of the enzyme was undergoing transport at any given moment.
|Number of pages
|Journal of neurochemistry
|Published - Feb 1979
ASJC Scopus subject areas
- Cellular and Molecular Neuroscience