A carboxy terminal fragment

Mallette LE, Tuma SN, Berger RE, Kirkland JL. Radioimmunoassay for the middle region of human parathyroid hormone using an homologous antiserum with a carboxy-terminal fragment of bovine parathyroid hormone as radioligand. J Clin Endocrinol Metab 1982 54 1017-24. 

Bivalent inhibitors of thrombin have been synthesized to bind the anion-binding exosite and active (catalytic) site of thrombin simultaneously. By coupling the carboxy terminal fragment of hirudin to a tripeptide (D-Phe-Pro-Arg) by including a spacer molecule, both the anion exosite and the catalytic site are blocked. An example of such a molecule is Hirulog, which has 20 amino acids and has a Kj of 2 nM (61). Its ability to block the active site has been questioned, since thrombin has been shown to cleave the Arg-Pro bond of Hirulog slowly in vivo (58). In addition to hirudin and hirudin-like compounds, three other classes of site-directed thrombin inhibitors deserve mention. 

Nyabi et al. (162) demonstrated that PSs with mutated Asp residues are catalyti-cally inactive. Unexpectedly, these mutated PSs are still partially processed into amino- and carboxy-terminal fragments by a presenilinase-like activity and are able to rescue PEN2 expression and nicastrin glycosylation, and then they become incorporated into large 440-kDa complexes, demonstrating that the catalytic activity of PS and its other functions in the generation, stabilization, and transport of the y-secretase complex can be separated and extends the concept that PSs are multifunctional proteins (162). 

Leban,J.J., Heyer, D., Landavazo, A., Matthews,J., Aulabaugh, A. Daniels, A.J. (1995) Novel modified carboxy terminal fragments of neuropeptide Y with high affinity for Y2 type receptors and potent functional antagonism at a Y type receptor. J. Med. Chem. 38, 1150-1157. 

Collective motions of secondary and supersecondary structures in proteins are important for understanding functionality. A unique collective motion has been detected by molecular dynamics dynamics simulations of the carboxy terminal fragment (CTF) of the L7/L12 ribosomal protein [79]. In the crystal state, the unit cell embodies eight units of CTF. A dimer has been proposed as a functional significant structure. MD simulations of the dimer [80] and of CTF immersed in a bath of 2352 SPC water molecules carried out in our laboratory, have shown that protein collective motions are not damped down. For this particular case, the simulations in vacuo are good enough for reproducing structural features and the dynamical behavior of the whole protein. 

Sanyal, G., Richard, L.M., Carraway, K.L., and Puett, D., 1988, Binding of amphiphilic peptides to a carboxy terminal tryptic fragment of calmodulin. Biochemistry 27 6229-6236. 

A two-site immunometric assay of undecapeptide substance P (SP) has been developed. This assay is based on the use of two different antibodies specifically directed against the N- and C-terminal parts of the peptide (95). Affinity-purified polyclonal antibodies raised against the six amino-terminal residues of the molecule were used as capture antibodies. A monoclonal antibody directed against the carboxy terminal part of substance P (SP), covalently coupled to the enzyme acetylcholinesterase, was used as the tracer antibody. The assay is very sensitive, having a detection limit close to 3 pg/mL. The assay is fiiUy specific for SP because cross-reactivity coefficients between 0.01% were observed with other tachykinins, SP derivatives, and SP fragments. The assay can be used to measure the SP content of rat brain extracts. 

The substrate specificity of ACE is low. ACE cleaves a variety of pairs of amino acids from the carboxy-terminal part of several peptide substrates. The conversion of ANGI to ANGII and the degradation of bradykinin to inactive fragments are considered the most important functions of ACE. Both peptides have profound impact on the cardiovascular system and beyond. ACE is thus an important target for ACE inhibitors. These compounds are frequently and efficiently used in the treatment of hypertension and cardiac failure. 

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