Carbonic anhydrase (CA)-related proteins (CA-RPs), and transmembrane proteins with CA or CA-RP domains.

Abstract

Members of the a-carbonic anhydrase (α-CA) gene family encode not only proteins that exhibit the characteristic catalytic activity of CA (i.e., the reversible hydration of CO2), but also CA-related proteins that are apparently devoid of this activity. For a recent summary of the activity mechanisms and functions of the mammalian CA isozymes, see Sly and Hu (1995). In amniotes (reptiles, birds, and mammals), the active CA isozymes have been designated, CA I — CA VII, CA IX, CA XII, and CA XIII, and the presumed inactive isoforms, CA-RP VIII, CA-RP X, and CA-RP-XI. In non-amniotes, apparently inactive α-CA-related proteins (CAH-RPs) have been identified in both the nematode, C. elegans, and in the yam (Dioscorea). Additional CA-related proteins are present as transmembrane proteins in several pox viruses, and as the CA-RP N-terminal domains of the extracellular regions of the transmembrane proteins of receptor protein tyrosine phosphatases β and γ (RPTPβ and γ). All of these presumably “acatalytic” CA-related isoforms probably either have no, or greatly diminished, CO2 hydration activity due to the substitution of one or more of the three histidine residues that are required to bind the zinc ion that is essential for efficient CA activity.KeywordsPurkinje CellCarbonic AnhydraseCarbonic Anhydrase ActivityChondroitin Sulfate ProteoglycanRenal Cell Carcinoma Cell LineThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.