ABSTRACT
Carpita and Delmar (1980), Carpita (1982), and Dugger and Palmer (1986) have shown that [14C] glucose or UDP[14C]-glucose incorporation into polysaccharides in cotton fiber during secondary wall formation predominantly labels 1 3- and 1,4-glucan. The amount of radioactivity in the individual -glucans was determined by analyzing the partially methylated alditol acetates from the [(14)C] glucans before and after treatment with Updegraff's acetic-nitric reagent. Hot acetic-nitric hydrolizes 1,3-glucan leaving resistant crystalline cellulose. In this research we have determined the mol wt characteristics of the crystalline cellulose polymer synthesized from [(14)C] glucose in intact cotton fibers. The [(14)C]-crystalline cellulose in the secondary wall was isolated using the acetic-nitric reagent, dissolved in a non-degrading solvent of lithium chloride /N,N-dimethylacetamide and separated on columns of Ultrastyragel by gel permeation chromatography. The [(14)C]-crystalline cellulose separates into individual cellulose chains with mol wts of 10(7) to 104. The weight average mol wt (Mw) of the polymer is 710,000. The distribution of the chains within the polymer approximates a normal distribution with 95% of the chains distributed within + 2 std dev of the mean typical of other biopolymers.
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