Carbonic anhydrase, aggregation

Micelles in water are described as spherical aggregates of a surfactant monomer27 30). They somewhat resemble to enzyme proteins in structures and functions, although the details are yet the subjects of recent controversies 29,30). There are numerous studies of micellar models of enzymes 28), but the examples of those of metalloenzymes are very few 31 37). In particular, there are no examples of micellar models of carboxypeptidase or carbonic anhydrase except ours 36,37). 

Fig. 1. Self-aggregation of Ca-binding systems from egg shell matrices, a) Highly purified organic Ca-binding systems after recombination b) CaC03 crystal formation upon aggregated Ca-binding systems after charging with Ca + and action of carbonic anhydrase...

Figure 1 Refolding and aggregation model for bovine carbonic anhydrase B (CAB). When denatured CAB in 5 M GuHCl is rapidly diluted to refolding conditions, the unfolded protein, U, forms the first intermediate, 1 This intermediate continues to refold to the second intermediate, L, which proceeds to fold to the native protein, N. If the unfolded protein is diluted to aggregating conditions, the first intermediate will associate to form multimers. The dimer, D, and trimer, T, species can further associate, resulting in the formation of large aggregates. (Reproduced from ref. 1. Copyright 1990 American Chemical Society.)...

Incubation in solutions of low denaturant concentration can sometimes cause inactivation. Formation of an incorrectly folded form of human carbonic anhydrase in 1.7M GuHCl which subsequently aggregates has been documented (77). Other proteins have also been observed to improperly refold at relatively low concentrations of denaturant These proteins include 6-galactosidase, tryptophanase, and elastase (6). 

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