18 This study showed that hMSCs cultured on surfaces with high concentrations of carboxylic acid exhibit upregulation of collagen type II. This was further supported by another study wherein carboxyl group-modified PEG hydrogels were used as 2D and 3D substrates to culture hMSCs. The modified surface maintained highest viable cell adhesion under chondrogenic conditions and showed early production of type II collagen, demonstrating the suitability of the substrate for the chondrogenic differentiation of hMSC. incorporated carboxyl functional groups on silane-modified glass surfaces and showed that carboxyl-coated surfaces induced chondrogenic differentiation of hMSCs in both basal and chondrogenic media. 7 One potential reason may be that carboxyl groups are the predominantly exposed functional groups of native cartilage, which is composed of glycosaminoglycans. Unlike the various functional groups discussed above, some studies have reported the preferential differentiation of hMSCs toward a chondrogenic lineage in the presence of carboxyl-modified surfaces. This enables carboxyl groups to be influential components of fatty acids and amino acids, which can be further reacted to generate esters, proteins, lipids, and alcohols within the body. When deprotonated, carboxylate anions are extremely stable due to resonance. This bestows unique properties of each individual group, creating a polar, highly electronegative, weakly acidic group capable of hydrogen bonding by both donating and accepting a proton.
Nair, in Biology and Engineering of Stem Cell Niches, 2017 2.4 Carboxyl GroupsĬarboxyl groups are a combination of two functional groups attached to a single carbon atom, namely, hydroxyl ( OH) and carbonyl ( O). This problem is thus similar to that of BNHS-type reagents in that the p I is altered, but in the opposite direction.Ĭhristina Klecker, Lakshmi S. One potential problem with this approach is that the biotinylation eliminates the charge of the carboxyl group, and the p I of the protein is thereby increased. The carbodiimide reacts temporarily with the carboxyl group, but is displaced by the biotin-containing reagent. The protein is treated with a water-soluble carbodiimide in the presence of a great excess of the biotin reagent.
Another type of reagent which is appropriate for this reaction is biotinyl cadaverine (biotin derivatized with a common diamine), also used in Section 2.1.2.5. The reaction is performed using biocytin hydrazide (the same reagent used to label sugar residues, but a different reaction chemistry). Biotinylation via Carboxyl GroupsĬarboxyl groups of proteins (glutamic and aspartic acids and the C-terminus) can be biotinylated using a biotin-containing reagent which bears a terminal amino group ( 11). BAYER, MEIR WILCHEK, in Immunoassay, 1996 2.1.2.2.
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