Collagen isoelectric point

Resilin has a greater percentage of acidic residues than collagen, elastin, and silk fibroin and contains fewer non-polar residues (i.e., Gly, Ala, Val, He, Leu, Pro, Met, and Phe) than silk fibroin and elastin. The significant content of acidic residues might account for resilin s hydrophilicity as well as its low isoelectric point, as indicated through swelling experiments [141, 145]. Resilin contains little to no... 

In dyeing the hair and the suede portion a number of factors must be allowed for. The keratin of the hair contains basically the same amino acids as the collagen of the skin but in a different ratio. The keratin of the hair includes cysteine, which cross-links the polypeptide chain and imparts stability. The collagen of the skin does not have these substances, and the cross-links are made by the tanning agent. On the other hand, only L-hydroxyproline can be found in the collagen. As a result the thermal stability is different, and in addition the isoelectric points of the two polypeptides diverge. 

These facts play an important factor in the dyeing behavior. The isoelectric point of hair is at a pH of ca. 5, whereas untreated collagen has its isoeletric point at a pH of ca. 6, which varies with the kind of tannage. For pure chrome suede it is close to pH 7 or about pH 6 after slightly anionic retanning. Consequently, for good dye fixation the acidification at the end of a dyeing is around pH 3 for fur hair and ca. pH 4 for chrome-tanned suede. 

Gelatin Derived from denatured collagen, its isoelectric point can be manipulated during formation to control charge. It has been modified for extended release of genetic material (61-63)... 

A weakly alkaline pH of 8 to 9 is the isoelectric point of collagen according to the literature as measured by the PAGl method. This means the electric repulsion between collagen molecules is at a minimum. This pH helps stable formation of HAp under the simultaneous titration condition used in this synthesis. 

Both complex coacervation and interfacial polymerization can be used to create a polymer coating. Complex coacervation involves a phase separation that results from the formation of a complex between oppositely charged polyelectrolytes. At a pH below its isoelectric point gelatin, a positively charged collagen hydrolysis product has been widely used in complex coacervation with anionic species like gum Arabic, pectin and alginate. This approach has been used to prepare scratch... 

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