Unique regulatory properties of the UDP-glucose:. beta. -1,4-glucan synthetase of Acetobacter xylinum. [Acetobacter xylinum]

Conference · Sat Jan 01 04:00:00 EST 1983 · J. Appl. Polym. Sci.: Appl. Polym. Symp.; (United States)

OSTI ID:7135286

Benziman, M; Aloni, Y; Delmer, D P

Conditions have been found for an extremely efficient transfer of glucose from UDP-glucose to a cellulosic ..beta..-1,4-glucan product, using enzyme preparations derived from cells of Acetobacter xylinum. Membrane fractions obtained by rupturing cells in the presence of 20% (w/v) polyethylene glycol-4000 (PEG-4000) exhibited UDP-glucose:..beta..-1,4-glucan synthetase activity 3- to 10-fold higher than those previously reported. Enzyme prepared in this fashion also shows a further marked activation by GTP. The activation (apparent K/sub alpha/ = 35 ..mu..M) is quite specific for GTP. A variety of other nucleotides and nucleotide derivatives had no effect on activity. Guanosine-5'-(lambda-thio)triphosphate, an analog of GTP, is even more efficient than GTP (K/sub alpha/ = 17 ..mu..M). Enzyme prepared in the absence of PEG-4000 does not respond to GTP because it lacks a protein factor essential for GTP activation. PEG-4000 promotes the interaction of the protein factor with the enzyme. The factor itself is devoid of synthetase activity and does not stimulate activity of the enzyme in the absence of GTP. Under optimal conditions, in the presence of GTP, factor, and PEG-4000, initial rates of enzyme activity that are 200 times higher than those previously reported can be achieved. Such rates exceed 40% of the in vivo rate of cellulose synthesis from glucose. 26 references, 3 figures, 3 tables.

• Research Organization: Hebrew Univ. of Jerusalem, Israel
• OSTI ID: 7135286
• Report Number(s): CONF-8205234-Vol.1
• Conference Information: Journal Name: J. Appl. Polym. Sci.: Appl. Polym. Symp.; (United States)
• Country of Publication: United States
• Language: English

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ACTIVATION ENERGY
ALCOHOLS
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BIOCHEMICAL REACTION KINETICS
BIOSYNTHESIS
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CELLULOSE
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SYNTHESIS
UDPG