Sulphate activation in higher plants

✍ Scribed by R. J. Ellis

• Publisher: Springer-Verlag
• Year: 1969
• Tongue: English
• Weight: 510 KB
• Volume: 88
• Category: Article
• ISSN: 0032-0935
• DOI: 10.1007/bf00396112

✦ Synopsis

ATP-sulphurylase was detected m extracts of roots and leaves of several species of higher plant. The enzyme occurs in the supernatant fraction, has a pH optimum of 8.0 and an absolute requirement for Mg ~+ ions. Sulphurylase activity is inhibited by selenate and molybdate but not by eysteine, methionine, glutathione, or thiol reagents. The synthesis of sulphurylase by turnip, lettuce, tomato, and Lemna plants grown under aseptic conditions is neither induced by sulphate nor repressed by cystine, and in the latter respect sulphate activation in plants differs from that in micro-organisms. APS-kinase could not be detected in extracts of any tissue although its product was stable under the conditions used. Sulphate, reduction in higher plants may thus proceed via adenylylsulphate and not via phosphoadenylylsulphate as in many micro-organisms.