Chitosan and alginate are polysaccharides. Chitosan is a polymer of D-glucosamine and N-acetylglucosamine, and alginate is a polymer with repeating unit of β-D-manuronil linked with α-L-guluronil. The lysozyme only recognizes glycosidic linkages between N-acetylglucosamine units. Therefore it is unable to hydrolyze the alginate.

Chitosan and alginate are polysaccharides. Chitosan is a polymer of D-glucosamine and N-acetylglucosamine, and alginate is a polymer with repeating unit of β-D-manuronil linked with α-L-guluronil. The lysozyme only recognizes glycosidic linkages between N-acetylglucosamine units. Therefore it is unable to hydrolyze the alginate.

Dear Hamed,

Lysozymes are enzymes present in plant and human that can hydrolyze the β(1-4) linkages between N-acetylglucosamine and glucosamine in chitosan and chitin according to the distribution and proportion of N-acetyl group. This enzyme is well described as dependent on N-acetyl degree and then is more active on chitin than chitosan because chitin has more N-acetyl glucosamine residues. For more information, this link could be interesting for you (https://www.researchgate.net/publication/265518866_Chitosan_as_an_adhesive)

Regards

Article Chitosan as an adhesive

Chitosan is basically the deactylated product of chitin. Chitin is one of the most abundant polysaccharide after cellulose having repeated units of N-acetyl-D-glucosamine and is insoluble in water. Inorder to make it soluble, deacetylation is carried out using NaOH so Chitosan is basically a polymer with random units of D glucosamine and N-acetyl D glucosamine.

Lysozyme normally cleaves glycosidic bonds between C-1 of N-acetyl muramic  and C-4 of N-Acetylglucosamine (which form the repeating units of peptidoglycan) and normally specifically attacks only the bond after identifying N acetyl D- glucosamine. This is the reason why Lysozyme also has capability to break chitin and so chitosan which is iits deacetylated product. However, alignic acid or alginate is polymer of rare mannuronic acid and guluronic acid linked through 1,4 linkage which cannot be identified by Lysozyme and hence it is stable in presence of this enzyme..

Dear all

Great thanks for your nice responses. So, if we can prepare a sample of alginate which has N-acetyl groups on its carboxylic moieties, the resulting polymer could be recognized by lysozyme?

Not necessarily, D glucosamine is more essential part to be recognized and of course beta 1,4 linkage.... You may not get the outcome as desired by you even after acetylation.

I don't know ;0)

Dear Dr. Agrawal

I'd like appreciate you. but a question. When you mentioned not necessarily, it means that it should be checked?

In other word, have you been ever found a report regarding the lyzosyme-based degradation of acetylated alginate in literature?

Sincerely

Chitosan & alginate are natural polymers “biopolymers”. Their natural biological compatibility & activity rendered them as promising candidates for various biomedical applications. Chitosan is derived from chitin, a type of polysaccharide that is found in the hard exoskeletons of shellfish like shrimp & crab. Chitin is one of the most abundant polysaccharides found in nature, making chitosan a plentiful & relatively inexpensive product.

Alginate is also a polysaccharide derived from brown seaweed. Like chitosan, alginate can be processed easily in water and is quite non-toxic & non-inflammatory; that is why it has been utilized in some countries for wound dressing & for use in food products.

Hamed, what she means by "not necessarily" is when you said --> So, if we can prepare a sample of alginate which has N-acetyl groups on its carboxylic moieties, the resulting polymer could be recognized by lysozyme?

It means N-acetyl part is only a minor part of the substrate recognition by the enzyme. The one that taken into account the most are the D-glucosamine and the beta 1-4 linkage. If you take a look on how different the monomer of both polysaccharides are, you'll see that the amine group of D-glucosamine and carboxyl group of D-mannuronic/L-guluronic acid are located in a completely different location. Carboxyl moiety of the D-mannuronic/L-guluronic acid is actually located on C6 which in D-glucosamine counterpart is hydroxymethyl group (CH2OH).

Dear Muhammad,

thanks for your answer. Regarding to the position of N-acetyl, I agree with you. But, I'd like to mention that the alginate has also beta 1-4 linkages in its chemical structure. So, I think this linkage could not be the major parameter. I look forward to hearing from you.

Regards.

Yes, that's true, but unless lysozyme is a non-specific enzyme like lipase or CYP450, then in my opinion lysozyme won't be able hydrolyze other substrate than chitosan/chitin. Carboxyl versus amine aside, there are 5 chiral atom in every monomer, which means every hydroxide/ether group must be in the correct position to be bound by the corresponding amino acid residue inside the binding cavity of lysozyme.

both polymer is polysaccaride but different in unit .