Cellulose biosynthesis by enzymes from the hypocotyl of the mung bean (Phaseolus aureus), as judged by the extraction technique of Updegraff (1969)

Andrew F.D. Kennedy
The numbers refer to the chapters concerned. 1. Current knowledge on cellulose biosynthesis was summarised. The section is divided into four main parts concerned with; A. the importance of cellulose; B. the structure of cellulose; C . cellulose biosynthesis, and; D. the cellular location of cellulose biosynthesis. Where relevant, cellulose biosynthesis in the cellulosic bacterium Acetobacten xylinum and algal systems was included. 2. This chapter presents the rationale behind this work and the
more » ... riteria used to assess the cellulosic nature of the synthesised products. 3. The materials and methods used in this work were described. 4. The incorporation of radioactivity from GDP-[U-14C]-G, UDP-[U-14G]-G, [U-14C]-sucrose, [U-14C]-glucose and [U-14C]-glucose-1-phosphate into the water-and chloroform: methanol (3:2 v/v)-insoluble products was investigated. It was found that the sugar-nucleotides were the most efficient substrates, that the incorporation of radioactivity from 1.0 mM UDP-[U-14c]-G into these products appeared to be substrate-activated, and that the products synthesised from UDP-[U-14C]-G at this concentration contained beta (1-3) linked glucose. The distribution of the enzymic activity utilising the sugar-nucleotides between wall and particulate fractions and the effect of storage of the enzymes at -20°C was also investigated. 5. The alpha-cellulose extraction was explained. Radioactivity from GDP-[U-14]-G, GDP-[U-14C]-M and UDP-[U-14C]-G was incorporated into alpha-cellulose. GDP-[U-14C]-M was found to be an efficient substrate and GDPM stimulated the incorporation of radioactivity from GDP-[U-14C]-G into this fraction. 6. The Updegraff extraction was introduced. Both UDP-[U-14C]-G and GDP-[U-14C]-G acted as substrates for Updegraff cellulose (U-cellulose) synthesis. The effect of prolonged periods of extraction of the water-and chloroform : m ethanol (3:2 v/v)-insoluble products in the Updegraff reagent and the effect of retaining the enzymes at -20 °C was studied. 7. The incorporation of radioactive gl [...]
doi:10.5525/gla.thesis.71553 fatcat:sk6w7dskabdclhofuk3e4yg32q