Biomaterial Database

Aspartic proteinases--Fourier transform IR studies of the aspartic carboxylic groups in the active site of pepsin. 1994

G Iliadis, and G Zundel, and B Brzezinski

Institute of Physical Chemistry, University of Munich, Germany.

Fourier transform (FTIR) difference spectra of pepsin minus diazoacetylnorleucine methyl ester (DAN) or minus diazoacetyl-L-phenylalanine methyl ester (DAP) modified pepsin, respectively, demonstrated that Asp-215 is not deprotonated in pepsin. The FTIR difference spectrum of pepsin minus 1,2-epoxyparanitrophenoxypropane (EPNP) modified pepsin demonstrates that Asp-32 is present in pepsin as CO2- anion. The position of the v(C = O) vibration demonstrates that no (O...H...O)- hydrogen bond between Asp-215 and Asp-32 is formed. Furthermore, no H3O+ is present in the active center. Studies of the complex of pepsin with the inhibitor pepstatin prove that the inhibitor removes the water from the active site and Asp-32 becomes protonated.

UI	MeSH Term	Description	Entries
D009646	Norleucine	An unnatural amino acid that is used experimentally to study protein structure and function. It is structurally similar to METHIONINE, however it does not contain SULFUR.	Norleucine, L-Isomer,L-Isomer Norleucine,Norleucine, L Isomer
D010434	Pepsin A	Formed from pig pepsinogen by cleavage of one peptide bond. The enzyme is a single polypeptide chain and is inhibited by methyl 2-diaazoacetamidohexanoate. It cleaves peptides preferentially at the carbonyl linkages of phenylalanine or leucine and acts as the principal digestive enzyme of gastric juice.	Pepsin,Pepsin 1,Pepsin 3
D010649	Phenylalanine	An essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE.	Endorphenyl,L-Phenylalanine,Phenylalanine, L-Isomer,L-Isomer Phenylalanine,Phenylalanine, L Isomer
D011487	Protein Conformation	The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).	Conformation, Protein,Conformations, Protein,Protein Conformations
D006860	Hydrogen Bonding	A low-energy attractive force between hydrogen and another element. It plays a major role in determining the properties of water, proteins, and other compounds.	Hydrogen Bonds,Bond, Hydrogen,Hydrogen Bond
D001224	Aspartic Acid	One of the non-essential amino acids commonly occurring in the L-form. It is found in animals and plants, especially in sugar cane and sugar beets. It may be a neurotransmitter.	(+-)-Aspartic Acid,(R,S)-Aspartic Acid,Ammonium Aspartate,Aspartate,Aspartate Magnesium Hydrochloride,Aspartic Acid, Ammonium Salt,Aspartic Acid, Calcium Salt,Aspartic Acid, Dipotassium Salt,Aspartic Acid, Disodium Salt,Aspartic Acid, Hydrobromide,Aspartic Acid, Hydrochloride,Aspartic Acid, Magnesium (1:1) Salt, Hydrochloride, Trihydrate,Aspartic Acid, Magnesium (2:1) Salt,Aspartic Acid, Magnesium-Potassium (2:1:2) Salt,Aspartic Acid, Monopotassium Salt,Aspartic Acid, Monosodium Salt,Aspartic Acid, Potassium Salt,Aspartic Acid, Sodium Salt,Calcium Aspartate,Dipotassium Aspartate,Disodium Aspartate,L-Aspartate,L-Aspartic Acid,Magnesiocard,Magnesium Aspartate,Mg-5-Longoral,Monopotassium Aspartate,Monosodium Aspartate,Potassium Aspartate,Sodium Aspartate,Aspartate, Ammonium,Aspartate, Calcium,Aspartate, Dipotassium,Aspartate, Disodium,Aspartate, Magnesium,Aspartate, Monopotassium,Aspartate, Monosodium,Aspartate, Potassium,Aspartate, Sodium,L Aspartate,L Aspartic Acid
D001665	Binding Sites	The parts of a macromolecule that directly participate in its specific combination with another molecule.	Combining Site,Binding Site,Combining Sites,Site, Binding,Site, Combining,Sites, Binding,Sites, Combining
D016282	Aspartic Acid Endopeptidases	A sub-subclass of endopeptidases that depend on an ASPARTIC ACID residue for their activity.	Aspartic Endopeptidases,Aspartyl Endopeptidases,Acid Endopeptidases, Aspartic,Endopeptidases, Aspartic Acid,Endopeptidases, Aspartyl
D017550	Spectroscopy, Fourier Transform Infrared	A spectroscopic technique in which a range of wavelengths is presented simultaneously with an interferometer and the spectrum is mathematically derived from the pattern thus obtained.	FTIR,Fourier Transform Infrared Spectroscopy,Spectroscopy, Infrared, Fourier Transform