UDPglucose pyrophosphorylase activity in the diatom Cyclotella cryptica. Pathway of chrysolaminarin biosynthesis
UDPglucose pryophosphorylase activity was detected in cell-free extracts of the diatom Cyclotella cryptica T13L Reimann, Lewin and Guillard. When assayed in the direction of UDPglucose formation, the enzyme had maximal activity at pH 7.8 and was stimulated by Mg/sup 2 +/ and Mn/sup 2 +/ ions. 3-Phosphoglycerate and inorganic phosphate had little effect on enzymatic activity, and the enzyme was relatively insensitive to feedback inhibition from UDPglucose. A glucan was formed from UDP-(/sup 14/C)glucose in cell-free extracts of C. cryptica. This glucan had a median molecular weight of 4600 (as determined by gel filtration chromatography) and could be hydrolyzed by laminarinase. Partial acid hydrolysis of the glucan resulted in the formation of glucose and laminaribiose, but not cellobiose. These results suggest that the synthesis of chrysolaminarin (the major storage carbohydrate of diatoms) occurs via the activity of UDPglucose pyrophosphorylase, followed by glucosyl transfer from UDPglucose to the growing ..beta..(1 ..-->.. 3)-linked glucan.
- Research Organization:
- Solar Energy Research Institute, Golden, CO
- OSTI ID:
- 5520681
- Journal Information:
- J. Phycol.; (United States), Vol. 23:3
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CARBOHYDRATES
BIOSYNTHESIS
PHOSPHOTRANSFERASES
ENZYME ACTIVITY
ACID HYDROLYSIS
BIOLOGICAL PATHWAYS
CARBON 14 COMPOUNDS
CHROMATOGRAPHY
DIATOMS
GLUCOSE
MOLECULAR WEIGHT
TRACER TECHNIQUES
ALDEHYDES
ALGAE
CHEMICAL REACTIONS
DECOMPOSITION
ENZYMES
HEXOSES
HYDROLYSIS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
LYSIS
MONOSACCHARIDES
ORGANIC COMPOUNDS
PHOSPHORUS-GROUP TRANSFERASES
PLANTS
SACCHARIDES
SEPARATION PROCESSES
SOLVOLYSIS
SYNTHESIS
TRANSFERASES
550201* - Biochemistry- Tracer Techniques