Buying Guide,Aprotinin is a single peptide chain with three disulfide bonds

The aprotinin peptide sequence is a critical aspect of understanding this important proteinase inhibitor. Derived from bovine lung tissue, aprotinin, also known as bovine pancreatic trypsin inhibitor (BPTI), is a single peptide chain comprising 58 amino acids. This intricate polypeptide chain folds into a stable, compact tertiary structure, characterized by a twisted beta-hairpin and a C-terminal alpha-helix. Crucially, the functional integrity of aprotinin relies on the presence of three disulfide bonds, which help to stabilize its three-dimensional conformation.

The precise amino acid sequence for bovine BPTI, and by extension aprotinin, has been extensively documented. It reads as follows: RPDFC LEPPY TGPCK ARIIR YFYNA KAGLC QTFVY GGCRA KRNNF KSAED CMRTC GGA. This sequence, with its specific arrangement of amino acids, dictates the protein's ability to inhibit serine proteases. For instance, the sequence RPDFC(1)LEPPYTGPC(2)KARIIRYFYNAKAGLC(3)QTFVYGGC(2)RAKRNNFKSAEDC(3)MRTC(1)GGA highlights the positions of the disulfide bridges, specifically at positions 5-55, 14-38, and 30-51. These bonds are vital for maintaining the active conformation of the inhibitor.

The peptide sequence of aprotinin is not merely an academic curiosity; it underpins its robust biological activity. Aprotinin functions as a broad-spectrum protease inhibitor, effectively blocking the activity of enzymes like trypsin and chymotrypsin. Its inhibitory potency is remarkable, with reported inhibition constants (Kis) for trypsin as low as 0.06 pM. This potent inhibitory action makes aprotinin invaluable in various biological and medical applications.

In cell biology, aprotinin is utilized as a protease inhibitor to prevent protein degradation during the lysis and homogenization of tissues and cells. This application is particularly relevant when studying sensitive proteins or when performing radioimmunoassays of polypeptide hormones, where enzymatic breakdown could lead to inaccurate results. The ability of aprotinin to preserve the integrity of peptides and proteins ensures reliable experimental outcomes.

The structural intricacies of the aprotinin peptide sequence have also been a subject of detailed scientific investigation. Researchers have elucidated the crystal structures of a peptide covalently bound to dengue virus serotype 3 (DENV-3) protease, which included aprotinin. Studying these structures provides profound insights into the molecular interactions between the inhibitor and its target proteases, furthering our understanding of protease inhibition mechanisms. Furthermore, specific segments of the aprotinin molecule, such as Peptide 30–51 SS, which comprises a significant portion of the beta-sheets and alpha-helix, have been analyzed to understand their contribution to the overall structure and function.

The chemical formula for aprotinin is C284H432N84O79S7, with a molecular weight of approximately 6480 Da. This complex formula reflects the substantial number of atoms involved in its 58-amino acid structure. The designation RV9G97MQ8B is another identifier associated with aprotinin, likely a unique database or substance code.

While aprotinin is a naturally derived polypeptide, synthetic peptides that mimic its binding site have also been designed and studied. For example, a synthetic 13-residue peptide, AC-Pro-Cys-Lys-Ala-Arg-Ile-DPhe-Pro-Tyr-Gly-Gly-Cys-Arg-NH2, has been synthesized to resemble the binding site of basic pancreatic trypsin. Such research contributes to the development of novel protease inhibitors with tailored properties.

The term amino acid is fundamental to understanding aprotinin, as it is the building block of this polypeptide. The specific arrangement of these amino acids in the aprotinin sequence is key to its biological function. The sequence type is generally considered complete, meaning the full chain of 58 residues is present and characterized.

Aprotinin is classified as a peptide and a blood modifier agent, specifically within the category of hemostatics. Its role as a potent inhibitor of plasmin and other proteolytic enzymes extends its therapeutic potential. While not explicitly detailed in the provided snippets, aprotinin has been approved as a drug by the FDA in 1993, indicating its established medical significance. The availability of aprotinin as Aprotinin, 30 Trypsin Inhibitory Units (TIU), further underscores its use in standardized assays and research applications.

In summary, the aprotinin peptide sequence is a precisely defined arrangement of 58 amino acids, stabilized by three disulfide bonds, that confers potent protease inhibitory activity. This fundamental characteristic, along with its structural features and biological interactions, makes aprotinin a significant molecule in both scientific research and potential therapeutic applications.