復(fù)習(xí)題2023生物化學(xué)

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一、解釋名詞

必需氨基酸、非編碼氨基酸、氨基酸殘基、亞基、簡單蛋白、綴合蛋白、肽鏈、蛋白質(zhì)的一級(jí)結(jié)構(gòu)、蛋白質(zhì)的二級(jí)結(jié)構(gòu)、蛋白質(zhì)的三級(jí)結(jié)構(gòu)、蛋白質(zhì)的四級(jí)結(jié)構(gòu)、蛋白質(zhì)的等電點(diǎn)、Edman降解

二、簡答問題

1.簡述蛋白質(zhì)一級(jí)結(jié)構(gòu)的解析方法。2.簡述蛋白質(zhì)N-端序列分析方法。

3.簡述常用于肽鏈裂解的蛋白酶有哪些？有哪些特征？4.比較由蛋白質(zhì)水解獲得氨基酸的方法與特征？5.闡述蛋白質(zhì)定性和定量分析的方法和原理？

三、思考題

某一條肽鏈經(jīng)酸水解后，分析其組成成分含5種氨基酸，其N-端十分簡單環(huán)化。經(jīng)CNBr處理后得到以游離的堿性氨基酸，Pauly反應(yīng)呈陽性。若用胰蛋白酶作用則得到兩個(gè)肽段；其一為坂口反應(yīng)陽性，另一個(gè)在280nm有強(qiáng)的光吸收，并呈Millon氏陽性反應(yīng)。求此肽的氨基酸排列順序，并指出它的等電點(diǎn)（pI）應(yīng)當(dāng)是大于、等于或小于pH7。

2023-9-20

一、解釋名詞

肽平面、拉氏構(gòu)象圖、蛋白質(zhì)的二級(jí)結(jié)構(gòu)/三級(jí)結(jié)構(gòu)/四級(jí)結(jié)構(gòu)、模體（motif）、結(jié)構(gòu)域、超二級(jí)結(jié)構(gòu)、蛋白質(zhì)折疊、蛋白質(zhì)分子伴侶、蛋白質(zhì)的變形與復(fù)性、蛋白質(zhì)組、蛋白質(zhì)組學(xué)

二、簡答問題

1．穩(wěn)定蛋白質(zhì)三維結(jié)構(gòu)的作用力主要有哪些？

2．比較蛋白質(zhì)的二級(jí)結(jié)構(gòu)/三級(jí)結(jié)構(gòu)/四級(jí)結(jié)構(gòu)的異同？

3．影響蛋白質(zhì)的二級(jí)結(jié)構(gòu)穩(wěn)定性的主要因素有哪些？請(qǐng)說明理由。4．蛋白質(zhì)產(chǎn)生四級(jí)結(jié)構(gòu)的意義是什么？5．蛋白質(zhì)折疊的基本規(guī)律？三、思考題

1．試描述蛋白質(zhì)折疊的全過程。2．蛋白質(zhì)的變形與復(fù)性有何異同？3．蛋白質(zhì)組學(xué)研究的內(nèi)容和基本方法？

4．瘋牛病是有病毒引起的傳染性疾病，你是否同意？請(qǐng)說明理由。

5．已知分子量為240000的蛋白質(zhì)多肽鏈的一些節(jié)段是?螺旋，而另一些節(jié)段是??折

疊，其分子展開長度為????X10-5cm。試問該肽分子中?螺旋和??折疊的百分率。

四、?翻譯成中文?

Proteinsarelargebiomolecules,ormacromolecules,consistingofoneormorelongchainsofaminoacidresidues.Proteinsperformavastarrayoffunctionswithinorganisms,includingcatalysingmetabolicreactions,DNAreplication,respondingtostimuli,andtransportingmoleculesfromonelocationtoanother.Proteinsdifferfromoneanotherprimarilyintheirsequenceofaminoacids,whichisdictatedbythenucleotidesequenceoftheirgenes,andwhichusuallyresultsinproteinfoldingintoaspecificthree-dimensionalstructurethatdeterminesitsactivity.

2023-10-11

一、解釋名詞

電泳、等電聚焦電泳、雙向電泳、離子交換層析、疏水作用層析、親和層析、聚焦層析、凝膠過濾層析、沉降系數(shù)二、簡答問題

1.SDS是何含義，其基本原理是什么？有哪些應(yīng)用？2.在蛋白質(zhì)一級(jí)結(jié)構(gòu)分析中，如何定位二硫鍵？

3.依制備用離心機(jī)的轉(zhuǎn)速，如何劃分低速、高速和超速離心機(jī)？4.多肽固相合成的基本原理是什么？

三、思考題

1.試描述蛋白質(zhì)分開和純化的常用方法和純化方案設(shè)計(jì)的基本思路。2.如何鑒定得到的蛋白質(zhì)是已經(jīng)純化的？

3.如何鑒定得到的蛋白質(zhì)的分子量？如何區(qū)分是單體蛋白或寡聚蛋白？4.凝膠過濾和SDS-凝膠電泳有何不同？?

四、?翻譯成中文?

Proteinpurificationpurpose?

ThepurposeofProteinpurificationiseitherpreparativeoranalytical.Preparativepurificationsaimtoproducearelativelylargequantityofpurifiedproteinsforsubsequentuse.Examplesincludethepreparationofcommercialproductssuchasenzymes(e.g.lactase),nutritionalproteins(e.g.soyproteinisolate),andcertainbiopharmaceuticals(e.g.insulin).Analyticalpurificationproducesarelativelysmallamountofaproteinforavarietyofresearchoranalyticalpurposes,includingidentification,quantification,andstudiesoftheprotein'sstructure,post-translationalmodificationsandfunction.Pepsinandureasewerethefirstproteinspurifiedtothepointthattheycouldbecrystallized.Purificationstrategies

Choiceofastartingmaterialiskeytothedesignofapurificationprocess.Inaplantoranimal,aparticularproteinusuallyisn'tdistributedhomogeneouslythroughoutthebody;differentorgansortissueshavehigherorlowerconcentrationsoftheprotein.Useofonlythetissuesororganswiththehighestconcentrationdecreasesthevolumesneededtoproduceagivenamountofpurifiedprotein.Iftheproteinispresentinlowabundance,orifithasahighvalue,scientistsmayuserecombinantDNAtechnologytodevelopcellsthatwillproducelargequantitiesofthedesiredprotein(thisisknownasanexpressionsystem).Recombinantexpressionallowstheproteintobetagged,e.g.byaHis-tag,

tofacilitatepurification,whichmeansthatthepurificationcanbedoneinfewersteps.Inaddition,recombinantexpressionusuallystartswithahigherfractionofthedesiredproteinthanispresentinanaturalsource.

Ananalyticalpurificationgenerallyutilizesthreepropertiestoseparateproteins.First,proteinsmaybepurifiedaccordingtotheirisoelectricpointsbyrunningthemthroughapHgradedgeloranionexchangecolumn.Second,proteinscanbeseparatedaccordingtotheirsizeormolecularweightviasizeexclusionchromatographyorbySDS(sodiumdodecylsulfate-polyacrylamidegelelectrophoresis)analysis.Proteinsareoftenpurifiedbyusing2Dandarethenanalysedbypeptidemassfingerprintingtoestablishtheproteinidentity.Thisisveryusefulforscientificpurposesandthedetectionlimitsforproteinarenowadaysverylowandnanogramamountsofproteinaresufficientfortheiranalysis.Thirdly,proteinsmaybeseparatedbypolarity/hydrophobicityviahighperformanceliquidchromatographyorreversed-phasechromatography.

Usuallyaproteinpurificationprotocolcontainsoneormorechromatographicsteps.Thebasicprocedureinchromatographyistoflowthesolutioncontainingtheproteinthroughacolumnpackedwithvariousmaterials.Differentproteinsinteractdifferentlywiththecolumnmaterial,andcanthusbeseparatedbythetimerequiredtopassthecolumn,ortheconditionsrequiredtoelutetheproteinfromthecolumn.Usuallyproteinsaredetectedastheyarecomingoffthecolumnbytheirabsorbanceat280nm.

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2023-10-18

一、解釋名詞

別構(gòu)效應(yīng)、別構(gòu)蛋白、別構(gòu)劑、協(xié)同效應(yīng)、波爾效應(yīng)、分子病二、簡答問題

血紅蛋白正協(xié)同效應(yīng)的兩種模型是什么？

鐮刀狀細(xì)胞貧血病(sickle-cellanemia）的分子機(jī)制H+、CO2和BPG對(duì)血紅蛋白結(jié)合氧的影響及機(jī)制蛋白質(zhì)進(jìn)化的四種情形

三、思考題

試比較肌紅蛋白和血紅蛋白結(jié)構(gòu)和功能的異同。試描述肌肉收縮的分子機(jī)制。

以血紅蛋白結(jié)合氧的機(jī)制為例，闡述蛋白質(zhì)結(jié)構(gòu)與功能的關(guān)系?

四、?翻譯成中文?

Proteinstructureisthethree-dimensionalarrangementofatomsinaproteinmolecule.Proteinsarepolymers—specificallypolypeptides—formedfromsequencesofaminoacids,themonomersofthepolymer.Asingleaminoacidmonomermayalsobecalledaresidue(chemistry)indicatingarepeatingunitofapolymer.Proteinsformbyaminoacidsundergoingcondensationreactions,inwhichtheaminoacidsloseonewatermoleculeperreactioninordertoattachtooneanotherwithapeptidebond.Byconvention,achainunder30aminoacidsisoftenidentifiedasapeptide,ratherthanaprotein.[1]Tobeabletoperformtheirbiologicalfunction,proteinsfoldintooneormorespecificspatialconformationsdrivenbyanumberofnon-covalentinteractionssuchashydrogenbonding,ionicinteractions,VanderWaalsforces,andhydrophobicpacking.To

understandthefunctionsofproteinsatamolecularlevel,itisoftennecessarytodeterminetheirthree-dimensionalstructure.Thisisthetopicofthescientificfieldofstructuralbiology,whichemploystechniquessuchasX-rayc