Triple Point Biologics' Aspartic Proteinases antibody catalog covers rabbit polyclonal antibodies raised against eight validated targets—BACE1, BACE2, cathepsin D, cathepsin E, pepsin A, renin, napsin A, napsin B, and the presenilin family—representing the principal bilobed, pepsin-fold endopeptidases active at acidic to neutral pH in mammalian systems. Aspartic proteinases share a conserved catalytic dyad of two aspartate residues and cleave substrate peptide bonds without forming a covalent enzyme-intermediate. They are encoded across compartmentally distinct settings: BACE1 and BACE2 are membrane-anchored proteases of the secretory pathway; cathepsins D and E are localized to lysosomes and endosomes, respectively; pepsin A is the primary gastric luminal endopeptidase; renin is a circulating aspartyl protease central to angiotensin I generation; napsin A and B are expressed in lung and kidney epithelia; and the presenilin proteins are the catalytic subunits of the γ-secretase complex. Each family member has a defined substrate repertoire and tissue distribution, making target-selective reagents an operational necessity in experimental design.

Triple Point Biologics has produced proteinase and proteinase-inhibitor antibodies since 1994, and this catalog reflects approximately 32 years of continuous antigen selection and validation work. Each rabbit polyclonal in this collection is raised against recombinant or synthetic antigen corresponding to defined epitope regions—for example, intracellular loop or prodomain sequences—to minimize cross-reactivity among family members sharing the pepsin fold. All antibodies are validated for Western blot (WB) and immunohistochemistry (IHC) using human tissue lysates and FFPE sections; a subset has additionally been Cross-reactivity to mouse and rat orthologues is indicated as validated or predicted based on sequence identity at the immunizing epitope, and is specified per entry rather than claimed categorically. Critically, every target in this collection has a corresponding recombinant protein produced in the same laboratory, available through the TPB recombinant protein catalog, providing a biochemically defined positive control from a single source.

These antibodies are in routine use across several research contexts: BACE1 and BACE2 in amyloid precursor protein processing and Alzheimer's disease pathway studies; cathepsin D in lysosomal biogenesis, autophagy flux, and breast cancer cell biology; pepsin A in gastric physiology and esophageal reflux models; and renin in renin-angiotensin-aldosterone system (RAAS) dissection. Researchers working with enzymatic activity readouts may find the protease activity assay guide and protease inhibitor screening guide useful as methodological references. For best practices on incorporating matched recombinant proteins as antibody loading controls and signal calibrators, see the recombinant protein positive controls guide. Full validation data, including lot-specific WB images and IHC photomicrographs, are documented on individual product pages and summarized at TPB quality and validation.