Octapeptide

Long-term hypercaloric intake such as a high-fat diet (HFD) could act as negative regulators on bone remodeling, thereby inducing bone loss and bone microarchitecture destruction. Currently, food-derived natural compounds represent a promising strategy to attenuate HFD-induced bone loss. We previously prepared a whey protein hydrolysate (WPH) with osteogenic capacity. In this study, we continuously isolated and identified an osteogenic and antioxidant octapeptide TPEVDDA from WPH, which significantly promoted the alkaline phosphatase activities on MC3T3-E1 cells and exerted DPPH radical scavenging capacity...

Adipokinetic hormones (AKHs) in Arthopoda are characterized by special sequence features including limited choices of amino acid residues in certain positions, such as Trp in position 8. Over 100 different AKHs have been described, but de novo sequencing of novel peptide hormones can be a challenge. In a project of analyzing corpora cardiaca extracts from two fly species, two different moths, a termite and a beetle for their AKHs, we noted specific patterns in the fragmentation spectra of octapeptides in electrospray Q-TOF experiments resulting from the presence of Pro in position 6...

Adipokinetic hormone (AKH) is a neuropeptide produced in the insect corpora cardiaca that plays an essential role in mobilising carbohydrates and lipids from the fat body to the haemolymph. AKH acts by binding to a rhodopsin-like G protein-coupled receptor (GPCR), the adipokinetic hormone receptor (AKHR). In this study, we tackle AKH ligand and receptor gene evolution as well as the evolutionary origins of AKH gene paralogues from the order Blattodea (termites and cockroaches). Phylogenetic analyses of AKH precursor sequences point to an ancient AKH gene duplication event in the common ancestor of Blaberoidea, yielding a new group of putative decapeptides...

OBJECTIVE: To perform a screening for Huntington disease (HD) phenocopies in a Swedish cohort. METHODS: Seventy-three DNA samples negative for HD were assessed at a tertiary center in Stockholm. The screening included analyses for C9orf72-frontotemporal dementia/amyotrophic lateral sclerosis (C9orf72-FTD/ALS), octapeptide repeat insertions (OPRIs) in PRNP associated with inherited prion diseases (IPD), Huntington's disease-like 2 (HDL2), spinocerebellar ataxia-2 (SCA2), spinocerebellar ataxia 3 (SCA3) and spinocerebellar ataxia-17 (SCA17)...

The cardiac bioavailability of peptide drugs that inhibit harmful intracellular protein-protein interactions in cardiovascular diseases remains a challenging task in drug development. This study investigates whether a non-specific cell-targeted peptide drug is available in a timely manner at its intended biological destination, the heart, using a combined stepwise nuclear molecular imaging approach. An octapeptide (heart8P) was covalently coupled with the trans-activator of transcription (TAT) protein transduction domain residues 48-59 of human immunodeficiency virus-1 (TAT-heart8P) for efficient internalization into mammalian cells...

AIM: Dietary approaches for the regulation of blood pressure are the need of the hour. Hence, identifying the foods possessing such activity is gaining importance. With this aim, moth bean (Vigna aconitifolia), an underutilized pulse, was explored for the presence of antihypertensive activity in terms of angiotensin converting enzyme (ACE)-inhibition bioactivity. METHODS: Defatted moth bean protein concentrate was hydrolyzed by using different proteases including Alcalase, papain, and trypsin, to identify the enzyme producing highly potent ACE inhibitory peptides...

The clinical success of radiolabeled somatostatin analogs in the diagnosis and therapy-"theranostics"-of tumors expressing the somatostatin subtype 2 receptor (SST2 R) has paved the way for the development of a broader panel of peptide radioligands targeting different human tumors. This approach relies on the overexpression of other receptor-targets in different cancer types. In recent years, a shift in paradigm from internalizing agonists to antagonists has occurred. Thus, SST2 R-antagonist radioligands were first shown to accumulate more efficiently in tumor lesions and clear faster from the background in animal models and patients...

Histidine-rich peptides (HRPs) have been investigated to create functional biomolecules based on the nature of histidine, such as ion binding and catalytic activity. The organization of these HRPs on a solid surface can lead to surface functionalization with the well-known properties of HRPs. However, immobilization of HRPs on the surface has not been realized. Here, we design a series of octapeptides with histidine repeat units, aiming to establish their self-assembly on a graphite surface to produce a highly robust and active nanoscaffold...

Prion protein misfolding is associated with fatal neurodegenerative disorders such as kuru, Creutzfeldt-Jakob disease, and several animal encephalopathies. While the C-terminal 106-126 peptide has been well studied for its role in prion replication and toxicity, the octapeptide repeat (OPR) sequence found within the N-terminal domain has been relatively under explored. Recent findings that the OPR has both local and long-range effects on prion protein folding and assembly, as well as its ability to bind and regulate transition metal homeostasis, highlights the important role this understudied region may have in prion pathologies...

Studies focusing on octapeptide repeat alteration mutations in PRNP in Alzheimer's disease (AD) and frontotemporal dementia (FTD) cohorts have been rare. We aim to screen sporadic AD and FTD patients with unknown etiology for the octapeptide repeat insertions and deletions in PRNP. Two hundred and six individuals were screened for alterations to the repeat region in the PRNP gene, including 146 sporadic AD and 60 sporadic FTD patients. Our study showed a 1.5% (3/206) occurrence of the octapeptide repeat alteration mutations in PRNP in a Chinese cohort of sporadic dementia...

Amatoxins are toxic bicyclic octapeptides found in certain wild mushroom species, particularly Amanita phalloides. These mushrooms contain predominantly α- and β-amanitin, which can lead to severe health risks for humans and animals if ingested. Rapid and accurate identification of these toxins in mushroom and biological samples is crucial for diagnosing and treating mushroom poisoning. Analytical methods for the determination of amatoxins are critical to ensure food safety and prompt medical treatment...

The conformation and function of somatostatin (SST), a cyclic neuropeptide, was recently found to be altered in the presence of Cu(II) ions, which leads to self-aggregation and loss of biological function as a neurotransmitter. However, the impact of Cu(II) ions on the structure and function of SST is not fully understood. In this work, transition metal ion Förster resonance energy transfer (tmFRET) and native ion mobility-mass spectrometry (IM-MS) were utilized to study the structures of well-defined gas-phase ions of SST and of a smaller analogue, octreotide (OCT)...

WCPFSRSF, an octapeptide (Trp-Cys-Pro-Phe-Ser-Arg-Ser-Phe), has been reported to improve memory in mice, but its gastrointestinal stability is unclear. The objective of this study was to evaluate the gastrointestinal stability of peptide WCPFSRSF and explore the neuroprotective potential of its digestive fragments. Results showed that the content of WCPFSRSF after gastric and gastrointestinal digestion decreased to 71.64% and less than 1%, respectively. Furthermore, the antioxidant and neuroprotective ability of WCPFSRSF were also affected...

Histone deacetylases (HDACs) are essential for the regulation of myriad biological processes, and their aberrant function is implicated in cancer, neurodegeneration, and other diseases. The cytosolic isozyme HDAC6 is unique among the greater family of deacetylases in that it contains two catalytic domains, CD1 and CD2. HDAC6 CD2 is responsible for tubulin deacetylase and tau deacetylase activities, inhibition of which is a key goal as new therapeutic approaches are explored. Of particular interest as HDAC inhibitors are naturally occurring cyclic tetrapeptides such as Trapoxin A or HC Toxin, or the cyclic depsipeptides Largazole and Romidepsin...

The N-terminus of the PRNP gene normally contains a 5-octapeptide repeat (R1-R2-R2-R3-R4), and insertions at this locus can cause hereditary prion diseases. In the present study, we found a 5-octapeptide repeat insertion (5-OPRI) in a sibling case of frontotemporal dementia. Consistent with previous literature, 5-OPRI rarely met the diagnostic criteria for Creutzfeldt‒Jakob disease (CJD). We propose 5-OPRI as a suspected causative mutation for early-onset dementia, especially the frontotemporal type.

In this study, the structural characteristics and active sites of the octapeptide (IIAVEAGC), the pentapeptide (IIAVE) and tripeptide (AGC) were studied in silica and in vitro . The quantum mechanics results show that the pentapeptide has better structural features. In addition, the docking of three peptides with Keap1 was compared through molecular docking, indicating that the potential molecular mechanism may show antioxidant activity by occupying the Nrf2 binding site on Keap1. The above results are consistent with the cell (SH-SY5Y cell) experiment...

BACKGROUND: Multiple system atrophy (MSA) is a progressive neurodegenerative disorder characterized by various combinations of autonomic failure, parkinsonism, and cerebellar syndromes. Although consensus criteria have been widely used to diagnose MSA, accurate clinical diagnosis remains challenging. Other neurodegenerative disorders, such as Lewy body disease, can mimic MSA. OBJECTIVES: We described clinical and neuropathologic findings of two patients with Creutzfeldt-Jakob disease (CJD) who had antemortem clinical diagnoses of MSA...

Increasing the copy number of peptides is an effective method to genetically engineer recombinant expression and obtain umami peptides in large quantities. However, the umami taste value of multicopy number umami peptides is lower than the single ones, thus limiting the industrial application of recombinantly expressed umami peptides. With aims to solve this problem, modification of an umami beefy meaty peptide (BMP) with trypsin hydrolysis sites was carried out via homology modeling and molecular docking in this study...

Naturally occurring peptides with high membrane permeability often have ester bonds on their backbones. However, the impact of amide-to-ester substitutions on the membrane permeability of peptides has not been directly evaluated. Here we report the effect of amide-to-ester substitutions on the membrane permeability and conformational ensemble of cyclic peptides related to membrane permeation. Amide-to-ester substitutions are shown to improve the membrane permeability of dipeptides and a model cyclic hexapeptide...

OBJECTIVE: This study aimed to investigate the correlation of serum octapeptide cholecystokinin-8 (CCK-8), substance P (SP), and 5-hydroxytryptryptamine (5-HT) values with depression levels in patients with post-stroke depression (PSD). It also aimed to explore the potential approach for the early diagnosis of PSD. PATIENTS AND METHODS: A correlation research between patients' biochemical indicators and depression levels was performed among 70 stroke patients during hospitalization from June 2021 to February 2022...