Calcitonin gene-related peptide has been extracted from the skin exudate of a single living specimen of the frog Phyllomedusa bicolor and purified to homogeneity by a two-step protocol. A total volume of 250 microl of exudate yielded 380 microg of purified peptide. Mass spectrometric analysis and gas phase sequencing of the purified peptide as well as chemical synthesis and cDNA analysis were c...

A new approach to on-resin detection of three model proteases (trypsin, chymotrypsin, and thrombin) has been developed, while at the same time already described methodology for simultaneous two enzymes (trypsin chymotrypsin) additionally generalized. Appropriate immobilized substrates, comprising specifically cleavable peptide sequences capped with fluorescent dyes, have synthesized on Rink Ami...

The carbonyl oxygen atom of the amide functional group is universally believed to be the thermodynamically preferred site of protonation in amides;[1] however, N protonation has been proposed to play a key role in biologically important reactions of peptides and proteins such as acid-catalyzed peptide hydrolysis[2] and cis ± trans isomerization about the CÿN bond.[3] Extensive research into the...

To determine the influence of glucagon-like peptides on the secretion of human pulmonary surfactant, we used human type II pneumocytes. In these cells, GLP-1(7-36) amide and exendin-4 stimulated phosphatidylcholine secretion (PC) and cAMP formation in a concentration-dependent manner; these effects were reversed by exendin(9-39). No changes were observed with other related peptides. The mechani...

Kisspeptin, a newly discovered neuropeptide, regulates gonadotropin-releasing hormone (GnRH). Kisspeptins are a large RF-amide family of peptides. The kisspeptin coded by KiSS-1 gene is a 145-amino acid protein that is cleaved to C-terminal peptide kisspeptin-10. G-protein-coupled receptor 54 (GPR54) has been identified as a kisspeptin receptor, and it is expressed in GnRH neurons and in a vari...

Context: The combination of peptide YY (PYY) and glucagon-like peptide-1 (GLP-1) has been proposed as a potential treatment for diabetes and obesity. However, the combined effects of these hormones, PYY3–36 and GLP-17–36 amide,on glucose homeostasis are unknown. Objective: To investigate the acute effects of PYY3–36 and GLP-17–36 amide, individually and in combination, on insulin secretion and ...

Herein are reported the mainchain (1)H, (13)C and (15)N chemical shift assignments and amide (15)N relaxation data for Escherichia coli DmsD, a 23.3 kDa protein responsible for the correct folding and translocation of the dimethyl sulfoxide reductase enzyme complex. In addition, the observed amide chemical shift perturbations resulting from complex formation with the reductase subunit DmsA lead...

2-Methoxy-4,4’-bis(methylthio)benzhydrylamine (10) and the corresponding disulfoxide were prepared and tested as a model amide protecting groups for their stability toward acidic conditions. Subsequently, the novel 4-[4,4’-bis(methylsulfinyl)-2-o~-(9-fluorenylmethylo~c~bonyl) benzhydrylaminolbutanoic acid (SCAL) handle (9) has been prepared and applied to solid-phase peptide synthesis of C-term...

Bovine pancreatic trypsin inhibitor (BPTI) is stabilized by 3 disulfide bonds, between cysteines 30-51, 5-55, and 14-38. To better understand the influence of disulfide bonds on local protein structure and dynamics, we have measured amide proton exchange rates in 2 folded variants of BPTI, [5-55]Ala and [30-51; 14-38]V5A55, which share no common disulfide bonds. These proteins resemble disulfid...