peripheral and integral protein

[Mr.Smoke]

Dear Friends,
I need your help in order to know about peripheral and integral protein.

[Poison]

What do you want to know about them?

[MrMistery]

peripheral proteins are soluble proteins which are attached by one way or another to the cellular membrane. they do not cross the cell membrane, but are attached to one side.
integral proteins cross the cell membrane and have a hidrophobic component(inside the membrane) and hidrophilic component(outside the membrane). Also there are some aminoacids present when the protein enters the membrane that keep it in place, and prevent it from sliding.

[Dr.Stein]

Need a figure?

[opuntia]

A picture to go with the explanation could make it easier to understand...so i think we need one

[MrMistery]

Here's a nice schematic picture. I got more beautiful ones, bu this seemed the best for understanding

[victor]

haha...I'll say the words that Dr.Stein hate.....the integral protein is alpha-helixed..

[MrMistery]

alpha-helixed? Is that a word?
And it is not even correct. Generally it is organised by alpha-helix. But sometimes it takes the shape of beta-barrels(like in the protein porin, in the inner mithocondrial membrane). With alpha-helix you need at least 7-8 aminoacids to cross the membrane, with beta-barrels it can be done with fewer=> molecular economy.

[victor]

Yup, she doesn't really like biochem..

[Mr.Smoke]

Thanks, for co-operation It really help me alot in understanding integral and peripheral protein in short cut.

[Dr.Stein]

Aww Victor, it seems that you take my four Aces now

Yeah, I only got C for biochem because of the alpha-helix and the gangs aargh grrrrr I admit that I am soo bad at "pure" biochem, I prefer "applied" biochem and can understand it much better, for instance: the biosynthesis of steroid hormones, the diversity of MHC, etc. etc... That's much more obvious rather than alpha-helix, beta-conformation, etc. etc. pfff