[erotavlas]

Hi, I wanted to detach the individual galactose units that make up carrageenan, but on both ends (where they attach to the repeating units - the linkages) I'm not sure what to put in its place.  I know its going to be a hydrogen for one side attached to the oxygen and the other side just a hydrogen maybe.  But how do I decide what goes where?  Basically I need something to fill in the missing galactose unit but smaller.

[Dan]

I don't really understand what you're trying to do. Are you asking how to do a hydrolytic digestion of carrageenan (hydrolyse the polymer into its monomers), or are you asking how to selectively remove only one terminal monomer from each end of the polymer?

The latter is probably impossible.

Basically I need something to fill in the missing galactose unit but smaller.

I don't follow this.

[erotavlas]

Sorry, its for a computational study.  I can't do a whole polymer since it will take too long to compute.  So ill break it into one individual unit to start. Does that help?

[Arkcon]

I've never heard of a terminal sucrase, or an exohexosase or something like.  Such enzymes do exist for DNA and proteins, but maybe someone else has heard of something that trims carbohydrate chains.

[Babcock_Hall]

When gangliosides are broken down, I think it is done one sugar at a time:  GM1 becomes GM2, which becomes GM3 in that way (a discussion of Tay-Sachs disease would be a good place to look).  With respect to the question put forward by the OP, I am not entirely sure, but I would be tempted to put the elements of water in place, in other words mimic a hydrolysis.

[Arkcon]

When gangliosides are broken down, I think it is done one sugar at a time:  GM1 becomes GM2, which becomes GM3 in that way (a discussion of Tay-Sachs disease would be a good place to look).  With respect to the question put forward by the OP, I am not entirely sure, but I would be tempted to put the elements of water in place, in other words mimic a hydrolysis.

OK, wiki ... wiki ... wiki ... (shut up) {click} {click} {click}  Oy, does the OP have their work cut out for them:  http://en.wikipedia.org/wiki/List_of_glycoside_hydrolase_families