Upper limit of molecular mass below which a molecule can permeate through porin

Range 600 to 700 Da
Organism bacteria
Reference Hengge R, Boos W. Maltose and lactose transport in Escherichia coli. Examples of two different types of concentrative transport systems. Biochim Biophys Acta. 1983 Aug 11 737(3-4):443-78. p.448 right column 3rd paragraphPubMed ID6349688
Primary Source Nakae T. Outer membrane of Salmonella. Isolation of protein complex that produces transmembrane channels. J Biol Chem. 1976 Apr 10 251(7):2176-8.PubMed ID773934
Method "This size limit has been determined by the ability of substrate loaded and porin containing liposomes to retain their substrate during Sephadex chromatography."
Comments "The porins are considered as molecular sieves that allow the permeation of molecules only below a certain size...Using carbohydrates this size limit has been determined to be Mr 600-700 [primary source]. Unfortunately, this simplified view has led to some misunderstanding in porin function. Even far below the size limit there are large differences in the rate of diffusion for two different molecules."
Entered by Uri M
ID 109800