Quinone tanning

The chitin is modified to impart the structure required by the functions of each particular tissue, via crystalHzation, deacetylation, cross-finking to other biopolymers (Fig. 1), and, in certain cases, quinone tanning. The resulting complex structures are capable of exceptional performances [15]. 

Fig. 7.7. Some of the covalent links which occur in structural proteins. ABCD represents one protein, EFB C G another. The N-terminal amino acid A is linked to an o-quinone which is also linked to a lysyl residue F(=quinone tanning) BB represents two tyrosyl residues coupled by a biphenyl linkage CC represents two cysteinyl residues coupled by a cystine linkage (as in keratin) D, E and G are not cross-linked. (After Brunet, 1967.)...

Fig. 7.8. Chemical reactions involved in quinone tanning. (After Smyth, 1969.)...

Waite J. H. (1983) Quinone-tanned scleroproteins. In The Mollusca (ed. K. M. Wilbur). Academic Press, New York, pp. 467-504. 

Ramalingham, K. (1973) The chemical nature of the egg-shell of helminths. 1. Absence of quinone tanning in egg-shell of the liver fluke Fasciola hepatica. Int. J. Parasitol 3 67-75. 

The occurrence of quinone tanning in DOPA protein systems and the high apparent catecholoxidase concentration suggests that exploration of the oxidation chemistry of peptidyl DOPA should be an important research... 

Muzzarelli, R.A.A., P. Ilari, W. Xia, M. Pinotti M. Tomasetti. 1994. Tyrosinase-mediated quinone tanning of chitinous materials. Carbohyd. Polym. 24 295-300. 

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