Alzheimer's and neurodegeneration research in this catalog is built around three protein-aggregation systems — amyloid-beta, tau and alpha-synuclein — plus the neurotrophins, synaptic markers and processing-pathway reagents used to characterise what happens around them. Our Alzheimer's topic page collects the peptide standards, antisera, labeled tracers and immunoassay kits for that work. This guide maps the families, explains why aggregation behaviour makes these peptides harder to handle than any others in the catalog, and sets out which reagent format answers which question.
What sits under the Alzheimer's topic
Families are filed here when the parent peptide or protein is an aggregation species, a processing intermediate, a synaptic or neuronal marker, or a trophic factor used in neurodegeneration models. That spans the amyloid precursor protein pathway, the tauopathies, synucleinopathies, prion biology as the mechanistic template for templated misfolding, and the neurotrophin families used to assess neuronal survival. Overlap with the neuropeptide topic is substantial, since somatostatin and galanin interneuron markers are standard readouts in these models. Every item is supplied for in-vitro and approved animal research only.
Amyloid-beta and the APP pathway
- Amyloid-beta — the central family: Aβ(1–40), Aβ(1–42), Aβ(1–43), the reversed Aβ(42–1) control, truncated and pyroglutamated species, and fluorescently labeled versions. Aβ42 aggregates far faster than Aβ40, which is why the two are never interchangeable in an aggregation assay.
- Aβ40 S26C — a cysteine-substituted variant used to prepare covalently stabilised dimers, one of the standard tools for isolating oligomer effects from fibril effects.
- APLP — amyloid precursor-like proteins, the APP family members used to test whether an observation is APP-specific.
- AICD — the APP intracellular domain released by gamma-secretase, studied as a signalling fragment in its own right.
- Presenilin — the catalytic core of gamma-secretase; peptide reagents support cleavage-site and inhibitor studies.
- SORL1 (SorLA) — an APP trafficking receptor and a confirmed Alzheimer's risk gene, increasingly ordered as the genetics-driven literature grows.
Tau, synuclein and prion families
- Tau — full-length isoforms, the repeat-domain fragments that form the fibril core, and phosphopeptide standards corresponding to the diagnostic phospho-epitopes. Phospho-site specificity is the whole point of most tau antisera, so the epitope specification matters more than the family name.
- Alpha-synuclein — monomer standards, familial mutant sequences and the NAC-region fragments used in aggregation work; central to Parkinson's and Lewy-body models as well as mixed pathology.
- Prion protein — PrP fragments including the neurotoxic PrP(106–126) peptide, used both for prion research and as the mechanistic template for templated protein misfolding generally.
- CHIP — the co-chaperone ubiquitin ligase directing misfolded tau and synuclein to degradation; a proteostasis reagent rather than an aggregation species.
Neurotrophic, synaptic and neuroprotective families
- BDNF and NGF — the two most-ordered neurotrophins, used as survival factors in primary culture and as biomarkers of plasticity in model tissue.
- Neurotrophin family — NT-3, NT-4/5 and the pro-forms, whose opposing p75 signalling is a distinct research question.
- CNTF — ciliary neurotrophic factor, and the origin of several designed neuroprotective peptide fragments.
- Neurogranin — a postsynaptic calmodulin-binding protein and one of the better-established synaptic-degeneration markers in CSF studies.
- Humanin — a mitochondrial-derived peptide originally identified in a screen for factors protecting against Aβ toxicity; the founding member of the mitochondrial peptide group.
- Nogo — myelin-associated inhibitor of neurite outgrowth, used in regeneration and plasticity studies.
- Somatostatin and galanin — interneuron populations reproducibly altered in Alzheimer's model tissue, ordered as immunohistochemical markers.
Which formats the Alzheimer's topic contains
Synthetic peptide standards supply the aggregation species themselves plus phosphopeptide calibrators and blocking peptides. Labeled peptides are heavily used: fluorescent Aβ for uptake and clearance imaging, biotinylated peptides for pull-down of binding partners. Polyclonal antisera carry most of the detection work, and in this topic epitope and phospho-specificity define the reagent — a pan-tau antibody and a pT181 antibody answer different questions. ELISA kits quantify Aβ40, Aβ42, total and phospho-tau and neurogranin in CSF, plasma and brain homogenate; the Aβ42/Aβ40 ratio is the standard reported readout rather than either value alone. Magnetic beads support immunoprecipitation of aggregates, and peptide libraries serve epitope mapping across tau and synuclein.
How laboratories choose within a family
The aggregation state is the experiment. Monomer, oligomer and fibril preparations of the same sequence produce different results, and no catalog item can supply "oligomers" as a stable product — they are prepared from monomer under a defined protocol. Order well-characterised monomer and generate the species you need. Sequence variant second: Aβ40 versus Aβ42, pyroglutamated versus full N-terminus, wild-type versus familial mutant synuclein. Epitope specification third for antibodies — phospho-site, conformational versus linear, and confirmed species reactivity. Fourth, for concentration in a sample, a validated kit is faster and far more reproducible than assembling components; use peptide plus antiserum for localisation and mechanism.
Handling notes for this topic
Amyloid-beta is the most handling-sensitive peptide in this catalog, and most irreproducibility in the literature traces to preparation rather than biology. The standard approach is to disaggregate lyophilised peptide in hexafluoroisopropanol, evaporate to a film, and store that film desiccated at −20 °C or below, then resuspend in DMSO immediately before use and dilute into buffer — never reconstitute Aβ42 directly into aqueous buffer and expect a monomer. Prepare fresh, use once, and record the protocol in the methods, because it determines the result. Tau and synuclein are more forgiving but still aggregate on freeze–thaw. General practice is in the solubility guide, the storage guide, the aliquoting guide and, for verifying content, the COA guide.
Where to go next
Browse the full Alzheimer's topic, the brain hub, or our overview of amyloid-beta, tau and alpha-synuclein reagents. Adjacent guides cover the neuropeptide section and the antibodies type guide, which matters here more than in most topics.