I am seeking the structural difference in between mucin from porcine stomach Type II and mucin type I–S from bovine submaxillary glands
Also is there any difference in terms of fermentability by the bacteria?
Thank you very much for your contribution in advance
Best
Cigdem
Hi Cigdem,
Mucin from the stomach has rather complex and long O-linked sugar chains (polylactosaminoglycans) while the submaxillmary mucin has mainly short (one or two sugars) O-linked chains.
Véronique
Bovine stomach mucin carries larger and more complex O-linked chains compared to the submaxillary mucin, which is characterized by oligosaccharides in the di- to trisaccharide core-type size range (sialyl-Tn, sialyl-T etc.). The stomach mucin carries mostly polylactosamine-type chains with blood-group-related peripheral structures and some organ-characteristic glycans, like those ending with alpha-linked GlcNAc.
Dear Cigdem Yucel,
Both of the products you are interested in contain a couple of mucin species: both membrane-bound and gel forming mucins. The different mucin species among others can be described by different mass, different protein sequence and different level and quality of glycosilation. The ratio of these molecules (and possibly minute amounts of other molecules) are not defined, this is why one of their application is as a component of complex culture media. "Type II" and "Type I" here refer to a classification of the company that produces it so that customers can easily differenciate between products by name. The biggest difference looking at the description of these products is that while the porcine stomach mucin contains ca. 1% sialic acids the bovine submaxillary mucin contains from 9-17% sialic acids. Sialic acids are terminal carbohydrate residues of the glycan chains on mucins and for this reason they are exposed to bacteria in vivo.
The fermentability can be vastly different depending on what is the organism in question. Since the possibly largest difference lies in the sialic acids between the two "substrates", (again, among other factors) the presence or absence of an enzyme repertoire making the organism able to cleave off and metabolize sialic acids can result in great differences. /although hard to say anything without knowing the exact experimental setup/
I hope I could contribute! :)
Regards,
Janos
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