Biomaterial Database

Proton nuclear magnetic resonance study of human plasma alpha-2-macroglobulin. 1986

H Arakawa, and Y Muto, and Y Arata, and A Ikai

A proton nuclear magnetic resonance (NMR) study is reported of human alpha-2-macroglobulin (alpha-2-M). It was observed that alpha-2-M, which consists of four identical subunits and has a molecular weight of 720,000, gives several sharp resonances. After cleavage of the "bait" region peptide with trypsin and subsequent removal of the peptide under a high salt condition, most of the sharp resonances disappeared, indicating that the sharp resonances observed in the native alpha-2-M originate from the amino acid residues in the bait region. Resonances due to the aromatic protons of the Tyr residue, which exists in the bait region, have been assigned on the basis of chemical shift. It was observed that the C3- and C5-H proton resonances for the Tyr residue are especially narrow, indicating that the side chain of the Tyr residue in the bait region is in a highly mobile state. Photochemically induced dynamic nuclear polarization experiments clearly show that the Tyr residue is actually exposed to the solvent. It was possible to identify resonances due to several His residues that are exposed to solvent. Other resonances, which probably originate from Arg residues in the bait region, were also observable in the conventional NMR spectra. On the basis of the present NMR data, we conclude that the bait region of the native alpha-2-M is highly flexible and exposed to solvent. On treatment of alpha-2-M with methylamine, no significant change has been detected in the NMR spectra observed in both the conventional and CIDNP mode.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D008744	Methylamines	Derivatives of methylamine (the structural formula CH3NH2).
D008970	Molecular Weight	The sum of the weight of all the atoms in a molecule.	Molecular Weights,Weight, Molecular,Weights, Molecular
D009682	Magnetic Resonance Spectroscopy	Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).	In Vivo NMR Spectroscopy,MR Spectroscopy,Magnetic Resonance,NMR Spectroscopy,NMR Spectroscopy, In Vivo,Nuclear Magnetic Resonance,Spectroscopy, Magnetic Resonance,Spectroscopy, NMR,Spectroscopy, Nuclear Magnetic Resonance,Magnetic Resonance Spectroscopies,Magnetic Resonance, Nuclear,NMR Spectroscopies,Resonance Spectroscopy, Magnetic,Resonance, Magnetic,Resonance, Nuclear Magnetic,Spectroscopies, NMR,Spectroscopy, MR
D010446	Peptide Fragments	Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.	Peptide Fragment,Fragment, Peptide,Fragments, Peptide
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
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000511	alpha-Macroglobulins	Glycoproteins with a molecular weight of approximately 620,000 to 680,000. Precipitation by electrophoresis is in the alpha region. They include alpha 1-macroglobulins and alpha 2-macroglobulins. These proteins exhibit trypsin-, chymotrypsin-, thrombin-, and plasmin-binding activity and function as hormonal transporters.	Slow alpha 2-Macroglobulins,alpha 2-Acute Phase Globulins,alpha-Macrofetoproteins,45S RNP,Acute-Phase alpha 1-Protein,Slow alpha 2-Globulin,alpha 1-Acute Phase Globulin,alpha 1-Acute Phase Protein,alpha 1-Macroglobulin,alpha 2-Acute Phase Globulin,alpha-Macrofetoprotein,Acute Phase alpha 1 Protein,RNP, 45S,Slow alpha 2 Globulin,Slow alpha 2 Macroglobulins,alpha 1 Acute Phase Globulin,alpha 1 Acute Phase Protein,alpha 1 Macroglobulin,alpha 1-Protein, Acute-Phase,alpha 2 Acute Phase Globulin,alpha 2 Acute Phase Globulins,alpha 2-Globulin, Slow,alpha 2-Macroglobulins, Slow,alpha Macrofetoprotein,alpha Macrofetoproteins,alpha Macroglobulins
D000595	Amino Acid Sequence	The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.	Protein Structure, Primary,Amino Acid Sequences,Sequence, Amino Acid,Sequences, Amino Acid,Primary Protein Structure,Primary Protein Structures,Protein Structures, Primary,Structure, Primary Protein,Structures, Primary Protein
D014357	Trypsin	A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC 3.4.21.4.	Tripcellim,Trypure,beta-Trypsin,beta Trypsin
D046911	Macromolecular Substances	Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.	Macromolecular Complexes,Macromolecular Compounds,Macromolecular Compounds and Complexes,Complexes, Macromolecular,Compounds, Macromolecular,Substances, Macromolecular