Chemical Forums

Specialty Chemistry Forums => Biochemistry and Chemical Biology Forum => Topic started by: briteyellowness on August 17, 2005, 08:44:45 AM

Title: papain vs. pepsin
Post by: briteyellowness on August 17, 2005, 08:44:45 AM
(it might not be a chem question, but i'm just giving it a shot)

i'm trying to see mixing with what will clumb with type A blood cells.

the answer was antibodies isolated from the serum of a type B patient and treated with papain.

i understand why it's anti B antibodies, but i picked treated with pepsin.  what's the difference between pepsin and papain.  i know they cut below and above the disulfide bond respectively, but that doestn' help me solve the question does it?

Title: Re:papain vs. pepsin
Post by: savoy7 on August 18, 2005, 01:55:13 AM
just some thoughts - not an answer

pepsin cleaves aromatic amino acids and tends to work at an acidic pH

papain works on the sulfide bonds, cysteine can activate it, tends to work at neutral pH and will spilt IgG by the hinge region.  The antibody forms 2 Fab fragments and 1 Fc fragment.  These fragments are then purified with an ion-exchange column or protein A.

From what i have read - pepsin tends to produce Fab' fragments while papain in the presence of cysteine produces Fab fragments

probably not much help to you

Title: Re:papain vs. pepsin
Post by: paperclip on August 18, 2005, 07:52:42 AM
I've been looking up the chemical activity of amide. Seems that amides aren't so reactive. But enzymes have a way of cleaving the amide into two.

Kelvar is a polyamide and so is nylon, the former having 'aromatic groups' while the latter is just 'straight chain alkane group attached'