Suberin chemical examination

Preliminary structural studies of cutin and suberin breakdown involved examination of 13C NMR spectra for insoluble residues that were resistant to chemical depolymerization. In cutin samples, flexible CH2 moieties in particular were removed by such treatments, but CHOCOR crosslinks and polysaccharide impurities were retained preferentially. A concomitant narrowing of NMR spectral lines suggested that the treatments produced more homogeneous polyester structures in both cases. Our current studies of cu-ticular breakdown also employ selective depolymerization strategies with appropriate enzymes (1,28). 

The designation of microscopic anatomical entities observed in various parts of plants as cutin, suberin, or even cutin-suberin-like material (Scott, 1966 Scott and Bystrom, 1970 O Brien and Kuo, 1975) had little chemical basis and therefore was quite arbitrary. Recent analyses of the chemical composition of such polymers allowed us to propose a tentative chemical basis for classifying these phytopolymers as shown in Table HI. The validity of the proposed criteria can be established only after examining the composition of a much larger number of polymer samples. The possibility that the content of midchain-modifled monomers in some suberins might be substantial and that some polymers might not fit such a classification must be recognized. 

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