分子生物学理论课

1、The Functions of ProteinsSickle Cell Anemia (镰刀形红细胞贫血)N-Val His Leu Thr Pro Glu Glu C(146) HbS peptideHbA peptideN-Val His Leu Thr Pro Val Glu C(146) Protein FunctionsEnzymes (酶): substrate binding, side chain in catalysisRegulatory factors (调节蛋白): insulin, growth factorsReceptors (受体)Signaling prot

2、eins (信号分子): adapter proteinsStructural proteins (结构蛋白): collagen, keratinMotor proteins (运动蛋白): actin, myosin and tubulinTransport proteins (转运蛋白): hemoglobinImmunoglobulin or Antibodies (抗体)Storage rpoteins (储存蛋白): casein and ovalbuminOthers Protein Classification by FunctionsEnzymesAn enzyme can

3、accelerate a reaction is because it can lower the energy barrier (activation energy) The exact mechanism of lowering the energy barrier depends on individual systems An enzyme does not change the Equilibrium Constant KAB+Ck1=10-4/sk2=10-6/sK=k1/k2=100Enzyme ClassificationOxidoreductases 氧化还原酶: 2A.2H

4、+O2=2A+2H2OTransferases 转移酶: A.X+B=A+B.X Acetyltransferase, methylase, protein kinase and polymeraseHydrolases 水解酶: A-B+H2O=AOH+BH Proteases, Nucleases, PhosphataseLyases 裂合酶: A.B=A+BIsomerases 异构酶: A=BLigases 连接酶: A+B+ATP=A.B+ADP+PiRegulatory Factors: InsulinReceptorsGPCRsRTKs(G protein-coupled rec

5、eptors)(Receptor tyrosine kinases)Intracellular Signaling PathwaysProtein kinasesProtein phosphataseThe phosphorylation cascade is the key for intracellular cell signalingMediated by protein kinases and phosphataseActivation of protein kinase A (PKA)GPCR (G Protein Coupled Receptor) Signalling Pathw

6、ayMotor Proteins: Muscle ContractionMolecular Components of a SacromereStructural Proteins: CollagenTransport Proteins: Myoglobin & HemoglobinMyoglobin (肌红蛋白)Hemoglobin (血红蛋白)The sigmoidal shape of hemoglobins oxygen-dissociation curve results from cooperative binding of oxygen to hemoglobinThis cha

7、racteristic of hemoglobin facilitates both the association and dissociation of oxygen with itCooperativity (协同效应) When a substrate binds to the active site of one enzymatic subunit, the rest of the subunits e active/inactivePositive cooperativity (正协同效应) or negative cooperativity (负协同效应) Antibodies:

8、 Structure and FunctionActivation of complement 活化补体系统 Activation of effector cells 活化效应细胞Immunohistochemistry (IHC) 免疫组化& Immunofluorescence (IF) 免疫荧光IHC Staining of Human Angiogenin in Prostate Tissue SamplesProstate tissue samples from normal (A), BPH (B), and cancer (C) patients were stained wit

9、h ANG antibody. (A) normal prostate tissue. (B) BPH and (C) prostate cancer tissues. Enzyme-Linked Immunosorbent Assay (ELISA) 酶联免疫吸附试验1) Obtain protein sample2) SDSProcedures of Immunoblotting:3) Transfer proteins from gel to nitrocellulose membrane using electrical current.ApplicationsTo detect if

10、 a specific protein of interest is present in a sampleTo compare the amounts of a protein of interest among different samplesTo detect the modification state of the proteinQuizUsing 2D gel separation, we found that protein A (number 3203) is upregulated in breast cancer tissue. Protein A is totally new and there are no reports for this gene. We only know the mRNA information of this gene. Please design an experiment to detect the localization of endogenous protein A in b