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J Wharfe

Publications and source records attributed to J Wharfe.

4 recordsLinked to original sources
PubMed1979

Lipid metabolism in germinating seeds. Purification of ethanolamine kinase from soya bean.

Ethanolamine kinase has been purified to homogeneity from germinating soya bean (Glycine max L.) seeds. The purified enzyme had a molecular weight of 17--19 000 as estimated by gel filtration and sodium dodecyl suphate-polyacrylamide gel electrophoresis. It would not phosphorylate choline, had a Km for ethanolamine of 8 microM and utilised Mg-ATP. The kinase could be purified in a 37 000 molecular weight form (dimer) which would easily dissociate on storage. In contrast to ethanolamine kinase whose activity was unaffected by the presence of choline in the assay system, soya bean choline kinase, although not phosphorylating ethanolamine, was competitively inhibited by the latter. The purification of specific choline and ethanolamine kinases from germinating soya bean confirmed in vivo observations which had indicated separate enzymes.

Choline↗
PubMed1978

The lipid composition of a barley mutant lacking chlorophyll b.

The acyl-lipid composition of a barley mutant that contained no detectable chlorophyll b was studied. This mutant contained chloroplasts that were much less organized than chloroplasts of normal barley. The mutant contained all the normal acyl lipids, with small increases in the relative concentration of phosphatidylglycerol and diacylsulphoquinoglycerides was unchanged, but most other lipids of the mutant barley contained lower amounts of alpha-linolenic acid compared with normal. There was no difference in the transhexadec-3-enoic acid content of phosphatidylglycerol, which was evidence against this lipid being involved in grana stacking.

Chlorophyll↗
PubMed1978

Fatty acid biosynthesis in the leaves of barley, wheat and pea.

1. The incorporation of radioactivity from [1-14C]acetate into the leaf lipids of barley, pea and wheat has been studied in pulse-labelling experiments. 2. There was little increase in the total labelling of lipids after the leaves were transferred to non-radioactive medium. However, there was an increase in the relative labelling of unsaturated fatty acids. In addition, there was an increase in the relative labelling of diacylgalactosylglycerol. 3. The principal radioactively labelled acyl lipids were diacylgalactosylglycerol and phosphatidylcholine. Phosphatidylcholine showed a decreasing proportion of [14C]oleate and an increasing amount of [14C]linoleate with time. Diacylgalactosylglycerol also had decreasing amounts of [14C]oleate but, in addition, had an increasing proportion of [14C]linolenate with time. 4. The absence of significant amounts of [14C]linolenate in phosphatidylcholine appeared to exclude a role for this phospholipid in linoleate desaturation. 5. The specific radioactivities of oleate and linoleate in phosphatidylcholine, diacylgalactosylglycerol and diacylgalabiosylglycerol were very similar in any single experiment. It was concluded that these fatty acids can rapidly exchange between the three intact lipids.

Diglycerides↗