please list the diffewrences between glycoprotein and proteoglycan
is there any criteria of percentage of the constituents to say that the given sample is one of these?

Asked by preethambasilmartis | 23rd Jun, 2016, 07:59: AM

Expert Answer:

Differences between glycoproteins and proteoglycans:

Point of Difference




Oligosaccharide (carbohydrate) chains are covalently attached to a polypeptide side chain

Glycosaminoglycan (GAG) chain(s) are attached to a polypeptide side chain

Nature of Chains

Oligosaccharide chains are short, branched, and may or may not be negatively charged.

Glycosaminoglycan chains are long, linearised, and negatively charged because of the presence of sulphate and uronic acid functional groups.

Non-protein Content

10 - 15% by weight

50 - 60% by weight


Broadly categorised as N-linked and O-linked saccharides.

Classification depends on the nature of the GAG chains.


Found on the cell surface with the carbohydrate chains placed outside the cell

Found in the connective tissues.


Act as integral membrane proteins, and play a role in cell-cell recognition and signaling

Provide structural support and mechanical strength to the extracellular matrix, play a role in the modulation of cell growth processes, and provide padding in joints.


ABO blood group antigens

Hormones like follicle stimulating hormone(FSH)



The sample can be tested for the presence of carbohydrate or protein content in order to judge whether the given sample is of glycoproteins or proteoglycans.

In proteoglycans, the carbohydrate moiety dominates, constituting about 95% or more of the mass of the complex.

In gycoproteins, the protein constitutes a larger fraction, generally 50% or more of the total mass.

Answered by Sheetal Kolte | 23rd Jun, 2016, 10:55: AM