生物化学教案第二章蛋白质(Proteins)

由天下分享时间：2025/1/29 21:54:40 加入收藏我要投稿点赞

课程名称__生物化学_

授课题目第二章蛋白质（Proteins）授课日期授课班级七年制授课时数 6学时授课方式多媒体第一节蛋白质的基本组成单位极其连接方式（Amino Acid Composition in Proteins）（2.0 学时）一、蛋白质的基本组成单位——氨基酸（Amino Acid Composition in Proteins- Amino acids）（一）蛋白质的元素组成及特点（Amino Acid Composition in Proteins）（二）氨基酸的结构与分类（Classification of Amino Acids） 1．氨基酸结构：L-α-氨基酸 2．氨基酸的分类：按侧链基团极性分类 1) 非极性疏水性氨基酸 2) 极性中性氨基酸 3) 碱性氨基酸 4) 酸性氨基酸（三）氨基酸的理化性质（Physical and Chemical Properties of Amino Acids） 1．两性电离与等电点（Amphoteric Dissociation and Isoelectric Point of Amino Acids）（概念） 2．紫外吸收（Ultraviolet Absorption and Colored Chemical Reaction of Amino Acids）（色氨授酸、酪氨酸、280纳米）课二、蛋白质分子中氨基酸的连接方式The Linkage of Amino Acids in Protein Molecules 内（一）肽键和肽的概念（Concept of peptide bond and peptide）容（二）氨基酸残基（三）寡肽、多肽、蛋白质 (oligopeptide, peptide, protein) 与（四）肽的方向性：氨基端至羧基端时三、生物活性肽 (Biologically Active Peptides) 间第二节蛋白质的分子结构 (Structure of Protein)（2.0学时）分一、蛋白质的一级结构(Primary Structure of Proteins) 配（一）概念：氨基酸排列顺序（二）序列分析二、蛋白质的空间结构 (Structure of Proteins) （一）构象的概念：蛋白质的多肽链经过其分子内部众多基团的折叠盘曲，形成特定的三维空间结构，即称为构象。空间结构决定着蛋白质的理化性质及功能（二）蛋白质的二级结构 (Secondary Structure of Proteins) 1．肽单元及其特征 (Peptide Unit) 2．蛋白质的二级结构的形式：α-螺旋、β-折叠、β-转角和无规卷曲 (? Helix, ? Sheet, ? Turn and Random Coil) 3．维持二级结构稳定的化学键：氢键 4．模体(Motif)的概念及形式：在许多蛋白质的分子中，具有二级结构的肽段相互靠近，形成具有特定功能的空间构象；或者仅是一个具有特定功能的很短的肽段,亦称超二级结构。模体的形式有：α-螺旋- β-转角- α-螺旋、锌指结构、亮氨酸拉链、RGD模体（三）蛋白质的三级结构(Tertiary Structure of Proteins) 1．三级结构的概念 2．维持三级结构稳定的化学键：次级键 3．结构域：蛋白质的三级结构常可分割成一个或数个球状或纤维状的区域，折叠得较为紧密，各行其功能，称为结构域

授课内容与时间分配（四）蛋白质的四级结构 (Quaternary Structure of Proteins) 1．概念：含有两条以上具有独立三级结构的多肽链(亚基)，多肽链间通过次级键相互连接形成的多聚体结构。 2．亚基三、蛋白质空间结构的确定 (Protein Structure Determination by X-ray Crystallography and NMR) 四、胶原蛋白的分子结构第三节蛋白质的结构与功能的关系 (Structure-Function Relationships of Proteins)（0.5学时）一、一级结构与功能的关系 (Relationships between Primary Structure and Function) （一）一级结构差异对功能的影响举例：胰岛素和核糖核酸酶（二）一级结构与物种进化的关系二、蛋白质空间结构和功能的关系 (Spatial Structure-Function Relationship) 举例：血红蛋白和肌红蛋白三、朊病毒与蛋白质构象病 (Protein Conformational Disease Caused by Perturbation of Protein Conformation) 四、蛋白质的分类 (Classification of protein) 第四节蛋白质的理化性质及其提取、纯化原理(Protein Physicochemical Properties and Principles of Purification)（1.0学时）一、理化性质 (Protein Physicochemical Properties) （一）两性解离与等电点 (Amphoteric Dissociation of Proteins) （二）胶体性质 (Colloidal Properties of Proteins) 分子直径大，不能透过半透膜蛋白质分子表面的水化膜和电荷是维持蛋白质在溶液中稳定的两个重要因素。（三）蛋白质的变性与沉淀 (Denaturation, Precipitation and Coagulation of Proteins) 1．变性：白质变性时，其氨基酸排列顺序没有改变，即其一级结构并未受到破坏 2．沉淀：沉淀的根本原因是破坏了蛋白质的水化膜及中和了蛋白质所带的电荷。蛋白质在其等电点时最易沉淀。沉淀的蛋白质不一定变性，变性的蛋白质也不一定沉淀。 3．凝固 4．蛋白质的变性与沉淀的实际应用（四）吸收光谱与呈色反应 (The Properties of Spectral Absorbance and Coloring Reactions) 1．吸收光谱 1) 紫外吸收的分子基础：色氨酸、酪氨酸 2) 紫外吸收的波长：280nm 3) 紫外吸收的应用：蛋白质定量分析 2．呈色反应：双缩脲反应、酚试剂反应二、提取与纯化原理 (Protein Purification) （一）盐析:中性盐可破坏蛋白质的水化膜并中和其电荷（二）离心技术（三）透析与超滤（四）凝胶过滤（五）电泳技术 1 第五节蛋白质组与蛋白质组学（0.5学时）一、蛋白质组（proteome）:指在特定条件下，一个组织细胞内所存在的全部蛋白质。

要求学生掌握的英文内容 All natural proteins are constructed from the same set of 20 ?-amino acids. With the exception of glycine, only L-amino acids exist in natural proteins. According to the variety of the side chains of these 20 amino acids in structure and functional groups, amino acids can be classified as neutral (non-polar hydrophobic and polar hydrophobic), basic, and acidic amino acids. The primary structure of proteins refers to the amino acid sequence. The amino acids in a polypeptide are linked by a peptide bond. The peptide bond is planar (peptide unit) because the C-N bond has partial double-bond character. The secondary structure of proteins refers to the conformation adopted by local regions of the polypeptide chain. The major elements of secondary structure are the ?-helix, the ?-strand, ?-turn, and random coil. Hydrogen bonds are the major linkages for stabilizing the structures. Motif refers to some arrangements of secondary structure elements that can occur in different protein structures such as helix-turn-helix motif and zinc finger motif found in many DNA-binding proteins. The tertiary structure of proteins describes the overall folding of the polypeptide chain including the spatial distribution of all atoms in the molecule. A long polypeptide strand often folds into multiple compact semi-independent regions (domains). Domains may perform different tasks in multifunctional proteins. The quaternary structure refers to the spatial arrangement of subunits in a multisubunit complex. The subunits are held together by noncovalent bonds. The primary structure of a protein determines its three-dimensional structure which determines its function. Insulin is a good example for studying the relationship between primary structure and function. Sickle-cell anemia is a molecular disease of individuals by a point mutation. Prion disease is a protein conformation disease. Mb and Hb functions in O2 storage and O2 transport respectively. The major secondary structure of Mb and Hb is ?-helix. Mb is monomeric; Hb is tetramer of 2 subunit types (?2?2 in adult). The saturation curve of Mb is hyperbolic, whereas that for Hb is sigmoidal as a consequence of its cooperative O2 binding. O2 binding causes he conformational change from 1

要求学生掌握的英文内容 T state to R state convenient to the binding of subsequent O2 to the next subunit. Globular proteins are hydrophilic and soluble in water, according to their electrostatic charges and hydration shell. Some physical and chemical factors can denature proteins by destroying the secondary bonds. The methods for separating and purifying proteins take advantage of properties such as charge, size, solubility, and affinity for their special ligands, which vary from one protein to the next. Proteome is the total set of proteins expressed in a given cell at a given time, the study of which is termed proteomics. There are many methods for proteomics including 2-DE, mass spectrometry, and so on. 1