|
|
||||||||
|
Plant Physiology 73:619-623 (1983) © 1983 American Society of Plant Biologists Reduction of N-Acetyl Methionine Sulfoxide in Plants 1Department of Biochemistry and Biophysics, University of California, Davis, California 95616
An enzymic activity which catalyzes the reduction of N-acetyl-methionine sulfoxide to L-N-acetyl-methionine has been observed in a wide variety of plant tissues. Its activity depended on the presence of dithiotreithol in the incubation medium. L-Methionine-sulfoxide was essentially inactive as a substrate. Of all the physiological reductants tested, only thioredoxin partially replaced dithiothreithol. When fractions obtained by gradient centrifugation of gently disrupted barley protoplasts were assayed for the reductase, the activity was largely associated with chloroplasts although approximately 15% was found in the cytosolic compartment. The enzyme, isolated from spinach chloroplasts, had a broad pH optima between 7.0 and 8.0, and its Km for N-acetyl methionine sulfoxide is 0.4 millimolar. The possible participation of this ubiquitous enzyme in enzyme regulation is discussed.
2 Present address: ARCO Plant Cell Research Institute, 6560 Trinity Court, Dublin, CA 94568. 1 Supported in part by the National Science Foundation, Grant PCM79-03976. This article has been cited by other articles:
|
|||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ASPB Publications | PLANT PHYSIOLOGY | THE PLANT CELL | |
|---|---|---|---|