Proteolytic Processing of APP Following discovery of the full-length APP cDNA clone, numerous studies were undertaken to detect the APP protein in cells and tissues. Full-length, membrane-bound forms of APP were readily detected by Western blotting, and it soon became apparent that a large, soluble, N-terminal fragment of APP (sAPPα) is released by the action of a putative "α-secretase" into conditioned tissue culture medium, cerebrospinal fluid, serum, and tissues such as brain.
IGF-1 IGF-1 is a single chain peptide consists of 70 amino acids in four domains, B, C, A and D. The A- and B-domains are structural homologs of the insulin A- and B-chains with 50% sequence similarity and domain C is the analogous to the connecting C-peptide in proinsulin, and the D domain in not found in insulin.
Introduction The β-amyloid precursor protein (APP) is connected to Alzheimer's disease by both biochemistry and genetics. As the source of the major constituent of amyloid plaques, APP has been the subject of many studies of its expression and metabolism.
GIP is a 42-aminoacid peptide secreted from the intestinal K-cells (located mainly in the duodenum and proximal jejunum) and released in response to nutrients, especially fats. The aminoacid sequence is not identical among mammalian species but there is 90% homology.