[hirenj]

Mucins aren't enzymes (as far as we know!), and the gut mucins are a bit different from those found on the endothelium, largely because they have different functions. The gut (and generally mucous epithelial) mucus is there for (amongst other things) clearing and maintaining a microbiome. Endothelial glycocalyx probably has some other mucin proteins, but also likely lots of mucin-like proteins, and the set of functions of these are much less clear.

[FollowingTheDao]

The enzyme MUC(1-whatever) makes mucin.

https://www.uniprot.org/uniprotkb?query=mucin&facets=model_o...

[hirenj]

I think what you mean is the MUC1-20 (ish, numbering is a bit sloppy but hopefully we can clean it up in near future) genes encode for mucins, that are synthesised on a ribosome, threaded into ER, shuffled off into the Golgi and then enzymatically modified by the enzymes encoded by the genes GALNT2, 7 & 10 (at least).

There are a further 20-30 ish enzymes that can modify the mucins as they are traversing the Golgi, and depending on the cell type, it can get packaged into vesicles (alongside calcium) for secretion.

So, they meet a lot of enzymes along the way, but harbour no catalytic activity themselves (as far as we know!).