名词解释 第一章 蛋白质的结构与功能

生物化学名词解释

第一章蛋白质

1.amino acid：An organic acid with an α-carbon atom linked to a carboxylic acid, an

amino group, a hydrogen atom, and a side chain (the R group). Twenty different amino acids are the building blocks of proteins.

2.peptide bond： A covalent linkage formed between the α-carboxyl group of one amino

acid and the α- amino group of another. Also known as an amide bond.

3.peptide: Two or more amino acids covalently joined by peptide bonds.

4.polypeptide: A long chain of amino acids linked by peptide bonds; the molecular weight

is generally less than 10,000.

5.Configuration. The spatial arrangement in which atoms are covalently linked in a

molecule.

6.Conformation. The spatial arrangement of atoms in a protein is called its conformation.

7.primary structure ：In a polymer, the sequence of amino acids and any interchain and

intrachain disulfide bonds of a protein. This sequence is specified by genetic information.

8.secondary structure：The localized conformation of a protein. As the polypeptide chain

folds, it forms certain localized arrangements of adjacent amino acids .

9.peptide unit: The six atoms of the peptide group (Cα1、C、O、N、H、Cα2) lie in a single

plane, with the oxygen atom of the carbonyl group and the hydrogen atom of the amide nitrogen trans to each other.

10.T ertiary structure ：The overall three-dimensional conformation of a protein in its

native folded state.

11.The molecular chaperones are large, multisubunit proteins that accelerate the folding

process by providing a protected environment where polypeptides fold into native conformations and form quaternary structures.

12.quaternary structure：In proteins containing more than one polypeptide chain, the

spatial arrangements of those chains (subunits) and the nature of contacts among them.

13.subunit: The independently three-dimensional structure in a protein with quaternary

structure.

14.allosteric effect：an effect that a small molecule, called an effector, noncovalently binds to

a protein and alters its activity.

15.Bohr effect : increase in the concentration of H+ and Pco2 reduces oxygen affinity to

hemoglobin

16.isoelectric point of protein: The pH at which a protein solute has no net electric charge

and thus does not move in an electric field.

17.denaturation of protein : Many physical and chemical reagents (urea or SDS, etc.) that

break noncovalent bonds disrupt secondary, tertiary, and quaternary structure of protein with attendant loss of biologic activity.