Question

What is sulfation and into which general type of reaction does it fall?

Answer 1

It's an enzyme-catalyzed sulfo-group transfer reaction. It's generally a biological group transfer reaction, but it might also be known as a "post-translational modification".

For instance, Tyrosylprotein sulfotransferase is an enzyme that transfers a sulfo group (not to be confused with a sulfate or sulfuryl group) from another compound onto Tyrosine. Basically:

The original oxygen is retained.

Here is a comparison of a sulfate group vs. a sulfo and sulfuryl:

The enzyme-catalyzed transfer reaction follows this mechanism.

Essentially, a sulfo group is transferred from the enzyme to a histidine (His, H) residue nearby, and it stays there until a nearby tyrosine (Tyr, Y) comes in to get it.