Carrier proteins, Channel formers, Glycoproteins & Proteoglycans

  

Carrier proteins

Channel formers

Carrier proteins are the integral proteins which extend into the lipid bilayer of cell membrane, and serve as channels for water soluble substances such as glucose and electrolytes.       When transporting the solutes, carrier proteins bind solute on one side of a membrane, undergo conformational changes, and release them on the other side of the membrane.     Career proteins bind solutes on one side of membrane and release it on the other side.   Carrier proteins have very slow transport rates   Carrier proteins are glycoproteins   Carrier proteins can mediate both active and passive transport.   Carrier proteins are synthesized on free ribosomes in the cytoplasm.   Carrier proteins can transport molecules or ions against the concentration gradient.   Carrier proteins move across the membrane     Carrier proteins transport both water soluble and insoluble substances.

Channel formers are ion selective, and contain a pore in which solute pass at high flux rates when the channel is open.         Channel formers include solute selectivity, a rapid rate of solute permeation, and gating mechanisms that regulate solute permeation.       Solutes diffuse through the pore of channel proteins   Channel formers have very first transport rates.   Channel formers are lipoproteins   Channel formers can mediate only passive transport.   Channel formers are synthesized on ribosomes bound to endoplasmic reticulum.   Channel formers can not transport molecules or ions against the concentration gradient.   Channel formers do not move while transporting molecules or ions.   Channel formers only pass water soluble molecules

 

Glycoproteins

Proteoglycans

A glycoprotein is a compound containing carbohydrate (or glycan) covalently linked to protein.   .  Glycoproteins are found on the cell surface with the carbohydrate chains placed outside the cell.   Glycoproteins act as integral membrane proteins, and play a role in cell-cell recognition and signaling.       Non-protein Content is 10 - 15% by weight.   These are broadly categorized as N-linked and O-linked saccharides.

Proteoglycans are proteins that are heavily glycosylated.The basic proteoglycan unit consists of a "core protein" with one or more covalently attached glycosaminoglycan (GAG) chain(s) .     Proteoglycans are found in the connective tissues.     Proteoglycans provide structural support and mechanical strength to the ECM, play a role in the modulation of cell growth processes, and provide padding in joints.     Non-protein Content is 50 - 60%by weight.   These are broadly categorized on the nature of the Glycosaminoglycan chains chains.