A subgroup of the band 7 domain of flotillin (reggie) like proteins. This subgroup contains proteins similar to stomatin, prohibitin, flotillin, HlfK/C and podicin. Many of these band 7 domain-containing proteins are lipid raft-associated. Individual proteins of this band 7 domain family may cluster to form membrane microdomains which may in turn recruit multiprotein complexes. Microdomains formed from flotillin proteins may in addition be dynamic units with their own regulatory functions. Flotillins have been implicated in signal transduction, vesicle trafficking, cytoskeleton rearrangement and are known to interact with a variety of proteins. Stomatin interacts with and regulates members of the degenerin/epithelia Na+ channel family in mechanosensory cells of Caenorhabditis elegans and vertebrate neurons and participates in trafficking of Glut1 glucose transporters. Prohibitin may act as a chaperone for the stabilization of mitochondrial proteins. Prokaryotic HflK/C plays a role in the decision between lysogenic and lytic cycle growth during lambda phage infection. Flotillins have been implicated in the progression of prion disease, in the pathogenesis of neurodegenerative diseases such as Parkinson's and Alzheimer's disease and, in cancer invasion and metastasis. Mutations in the podicin gene give rise to autosomal recessive steroid resistant nephritic syndrome.

alpha-amylase; Provisional

alpha-amylase

Alpha amylase catalytic domain found in archaeal, bacterial, and plant Alpha-amylases (also called 1,4-alpha-D-glucan-4-glucanohydrolase). AmyA (EC 3.2.1.1) catalyzes the hydrolysis of alpha-(1,4) glycosidic linkages of glycogen, starch, related polysaccharides, and some oligosaccharides. This group includes AmyA from bacteria, archaea, water fleas, and plants. The Alpha-amylase family comprises the largest family of glycoside hydrolases (GH), with the majority of enzymes acting on starch, glycogen, and related oligo- and polysaccharides. These proteins catalyze the transformation of alpha-1,4 and alpha-1,6 glucosidic linkages with retention of the anomeric center. The protein is described as having 3 domains: A, B, C. A is a (beta/alpha) 8-barrel; B is a loop between the beta 3 strand and alpha 3 helix of A; C is the C-terminal extension characterized by a Greek key. The majority of the enzymes have an active site cleft found between domains A and B where a triad of catalytic residues (Asp, Glu and Asp) performs catalysis. Other members of this family have lost the catalytic activity as in the case of the human 4F2hc, or only have 2 residues that serve as the catalytic nucleophile and the acid/base, such as Thermus A4 beta-galactosidase with 2 Glu residues (GH42) and human alpha-galactosidase with 2 Asp residues (GH31). The family members are quite extensive and include: alpha amylase, maltosyltransferase, cyclodextrin glycotransferase, maltogenic amylase, neopullulanase, isoamylase, 1,4-alpha-D-glucan maltotetrahydrolase, 4-alpha-glucotransferase, oligo-1,6-glucosidase, amylosucrase, sucrose phosphorylase, and amylomaltase.

alpha-amylase