> > > Mammalian Proteins are Glycosylated - this process is inherently heterogeneous. Most of proteins that are produced in humans and other mammals are covered with glycans (sugars) of varying length (1-20 monomer sugars).

Extracellular ones yes, but it's less common for cytoplasmic proteins.

On the other hand, you have a crapton of other modifications that are common on intracellular proteins. Phosphorylation, methylation, acetylation, acylations in general, SUMOylation, ubiquitination, neddylation, succinylation and so on and on.