发现胰岛β细胞所分泌的一种新激素

早在1900年,有人发现,胰岛内有淀粉样的蛋白质存在。但近一个世纪来,对它的化学性质、生理作用和临床意义却一直不十分了解。1987年,美国Westermark等从胰岛瘤患者的胰岛淀粉样蛋白中分离出一种分子量为3850、由37个氨基酸组成的多肽,称其为胰岛淀粉样多肽(Islet amyloid polypeptide,IAPP或Amylin),结构如下:Lys—Cys—Asn—Thr—Ala—Thr—Cys—Ala—Thr—Gln—Arg—Leu—Ala—Asn—Phe—Leu—Val—His—Ser—Ser—Asn—Asn—Phe—Gly—Ala—Ile—Leu—Ser—Ser—Thr—Asn—Val—Gly—Ser—Asn—Thr—Tyr     

小鼠SNP与Car2、Gpi1基因多态性的关联性

目的研究单核苷酸多态性(single nucleotide polymorphism,SNP)与小鼠生化标记基因Car2、Gpi1多态性间的关联性。方法从DNA、cDNA和蛋白多肽3个方面分析研究Car2与Gpi1基因的多态性。结果 Car2基因DNA和cDNA中有3个SNP与Car2a/b多态性相关,分别为外显子2中的C(T)、G(C)和外显子7中的A(G);蛋白多肽中发现第38位Gln/His与Car2a/b多态性相关,对应于外显子2中的G(C)。Gpi1基因DNA中没有发现与Gpi1a/b多态性相关的SNP;cDNA水平有2个SNP与Gpi1a/b多态性相关,分别为外显子9中的T(C)和18中的A(G);蛋白多肽中发现第247位Phe/Leu与Gpi1a/b多态性相关,对应于外显子9中的T(C)。结论 Gln/His(38)、Phe/Leu(247)间的转换可能分别是近交系小鼠形成Car2a/b,Gpi1a/b多态性的原因。     

浙江地区青霉素耐药肺炎链球菌PBPs基因及氨基酸序列研究

为阐明温州地区青霉素耐药肺炎链球菌（PRSP）的青霉素结合蛋白（PBPs）的基因和氨基酸序列的变异特点,对温州医学院自2000年11月～2004年1月收集的26份肺炎链球菌进行分离、鉴定及青霉素药敏实验,并对每株链球菌的PBP1A、PBP2B、PBP2X基因进行PCR扩增和直接测序,通过序列比对与生物信息学分析。结果表明,研究中的PBP1A的主要突变位点是保守基序KTG之后的4个连续氨基酸替换Thr574Ala、Ser575Thr、Gln576Gly、Phe577Tyr和保守序列STMK内的氨基酸替换Thr371Ser;PBP2B的主要突变位点是保守序列SSN之后的氨基酸替换Thr451Ala;PBP2X的主要突变位点是保守基序STMK 内的氨基酸替换Thr338Ala。以上突变类型以及菌株的青霉素耐药水平与文献报道相符。研究检测的PRSP的PBPs基因中暂未发现本地区特有的（新的）基因突变,也未检测出文献报道的某些与青霉素抗性相关的氨基酸替换。     

大肠杆菌热稳定性肠毒素的分离纯化和氨基酸顺序测定

上海市儿童医院婴儿腹泻病患中分离到产肠毒素的菌株,该菌株只产热稳定性肠毒素,经CAD-44树脂吸附,SephadexG-25凝胶过泸,DEAE-Seharose CL-6B离子交换层析,反相高压液相层析分离纯化后,用手工固相DABITC/PITC双偶合Edman降解法测定其氨基酸顺序为:Asn·Ser·Ser·Asn·Tyr·Cys·Cys·Gly·Leu·Cys·Cys·Asn·Pro·Ala·Cys·Thr·Gly·Cys·Tyr。     

人前列腺癌细胞系PC-3中PTI-1 cDNA的克隆及序列分析

为获取人前列腺癌诱导基因家族新成员 ,以人前列腺癌细胞系PC 3的总RNA为模板 ,用RT PCR方法扩增人前列腺癌诱导基因 1(PTI 1) ,将其亚克隆至克隆载体pUC19,进行测序 .将克隆得到的PTI 1基因片段与国外报道的人PTI 1基因编码区cDNA同源性为 99.3% ,但第 72 6、74 6、116 7、12 70、132 6、144 9、16 94和 16 95位碱基分别由A、A、C、C、A、A、T和C替代了文献中的C、C、G、G、G、C、C和T .其中 6个碱基的不同 ,导致了第 36、183、2 17、2 36、2 77和 35 9位密码子代表的氨基酸分别由Lys替代Gln ,Arg替代Gly ,Ala替代Gly ,Ser替代Gly ,Thr替代Pro和Arg替代Cys .将所获得的基因在GenBank登录 ,登录号为AF3974 0 3.结果提示 ,获得了PTI 1家族新成员 ,并且与EF 1α分子的同源性较已报道的PTI 1高 .     

榕江香猪生长激素基因的鉴定及功能分析

生长激素是调节动物生长的主要激素.本研究应用聚合酶链式反应技术从榕江香猪的基因组文库中分离出1.903kb生长激素基因.克隆的生长激素基因由五个外显子和四个内含子组成.榕江香猪生长激素基因的碱基序列与已知四个国外猪种和9个中国地方猪种之间的同源性为97%～99%,其间的差异主要集中在内含子2和4.通过限制性内切酶（DdeI,NarI,BsmNI）分析,鉴定出榕江香猪生长激素基因的五个多态性位点,分别位于5＇-侧翼区274（T/C）位点,外显子2的622（G/A）和631（G/A）位点,内含子2中的841（T/C）以及外显子4中的1 358（A/G）位点.同时,1 358（A/G）位的碱基改变导致榕江香猪生长激素成熟肽第108位异亮氨酸替换,三维结构分析表明,异亮氨酸的存在可能导致生长激素与受体间亲合力降低.     

贵州白山羊GOLA-DQA1基因多态性及生物信息学分析

目的:通过筛选贵州白山羊GOLA-DQA1基因SNPs位点,为进一步研究MHC基因多态性与山羊免疫性状的相关性提供依据。方法:选取同一生长环境中的贵州白山羊母羊157只构建品种DNA池并进行测序,结合SNPs位点测序峰高比值估算等位基因频率,利用软件对不同基因型的RNA和蛋白质二级结构进行预测。结果:在贵州白山羊DQA1基因发现6个SNPs位点G+2930A(同义突变)、T+2959C(Asn→Ser)、G+3061A(Pro→Leu)、A+3082G(Me→Thr)、C+3463A(Trp→Cys)、C+3525T(Arg→His)。生物信息学分析发现,C+3463A变异位点使RNA二级结构更加稳定;A+3082G变异导致自由能增加,稳定性降低。蛋白质结构预测发现除A+3082G基因型与原序列具有相同的二级结构外,其他基因型均引起蛋白质二级结构的改变。结论:贵州白山羊GOLA-DQA1基因具有丰富的多态性,但SNPs位点等位基因频率差异较大。     

小型猪葡萄糖转运子4外显子4a的基因多态性分析

目的分析我国特有的3个小型猪品系巴马小型猪、中国农大小型猪、五指山小型猪葡萄糖转运子4基因外显子4a的单核苷酸多态性（SNPs）分布特点,为我国小型猪在糖尿病和代谢性疾病研究中提供基础资料。方法以3个品系小型猪基因组DNA为模板,应用特异性引物进行PCR扩增,扩增产物纯化测序,进行BLAST比对分析。结果在小型猪GLUT-4基因外显子4a上有2个SNP位点：SNP1：GCT→GCC（Ala133 Ala）,3个品系均发生了变化,均为纯合突变,其突变率为（22/22,100%）。SNP2：GGC→GGT（Gly146 Gly）,巴马小型猪突变率为（6/6,100%）,均为纯合突变;五指山小型猪突变率为（6/6,100%）,均为纯合突变;中国农大小型猪突变率为（10/10,100%）,其中包括6例纯合突变（6/10,60%）和4例杂合突变（4/10,40%）。结论SNPs1,在所有测定的小型猪品系中检出,这可能是所测小型猪的共有特征。SNPs2可能是小型猪品系之间的差异。     

贵州地方山羊ADIPOQ基因外显子1和3多态性研究

为分析山羊ADIPOQ基因的多态性,筛选出对山羊繁殖性状有显著影响的SNPs位点,本研究以黔北麻羊和贵州黑山羊为试验对象,构建池DNA,采用PCR产物直接测序法对2个品种山羊该基因的外显子1和3进行单核苷酸多态性检测,估算各SNPs等位基因频率,并利用在线软件预测不同基因型的m RNA二级结构。结果显示,4对引物扩增片段均存在多态性,共发现5个单碱基突变,分别位于内含子1中的C109G,外显子3中的A730G、G1055A、A1691T和A2244G。利用生物信息学软件对外显子3中的A1691T、A2244G进行分析,结果表明2个SNPs位点均导致编码的m RNA二级结构发生改变。表明ADIPOQ基因在黔北麻羊和贵州黑山羊群体中存在较高的遗传多样性,ADIPOQ位点有望丰富两个山羊品种繁殖性状的研究内容。     

新生儿基因CYP2E1 5′端RsaⅠ和PON2311位点多态性与早产的关系

探讨新生儿基因细胞色素P450 2E1（CYP2E1）5‘端RsaI多态性和对氧磷酶2（二乙基对硝基苯磷酸酯酶2）基因311位点（PON2311）多态性对早产的影响。采用横断面调查方法,使用统一的调查表,由安庆市各县医院对入院分娩孕妇及其单胎,活产,早产和对照新生儿进行调查,共得到有效样本194个母亲－新生儿对。单因素分析结果显示：CYP2E1野生纯合子基因型（cut/cut)与突变纯合子基因型（uncut/uncut)/杂合子基因型（cut/uncut)比较,对早产的影响不具有统计学意义,而PONS2 Ser311Ser纯合子基因型与Cys311Cys纯合子基因型／Cys311Ser杂合子基因型比较,对早产的影响具有显著的统计学意义。进一步分析CYP2E15‘端RsaI位点多态性和PON2311位点多态性是否存在交互作用。结果显示：CYP2E1野生纯合子基因型和PON2 Ser311Ser纯合子基因型这一组合与参照组比较,对早产的影响具有显著的统计学意义。基因CYP2E15‘端Rsa I位点多态性与新生儿早产不相关,但基因PON2311位点多态性与新生儿早产相关,且CYP2E1 5‘端RsaI位点多态性和PON2311位点多态性之间对早产的影响存在交互作用。     

The amino acid sequence of human chorionic gonadotropin. The alpha subunit and beta subunit.

The amino acid sequences of both the alpha and beta subunits of human chorionic gonadotropin have been determined. The amino acid sequence of the alpha subunit is: Ala - Asp - Val - Gln - Asp - Cys - Pro - Glu - Cys-10 - Thr - Leu - Gln - Asp - Pro - Phe - Ser - Gln-20 - Pro - Gly - Ala - Pro - Ile - Leu - Gln - Cys - Met - Gly-30 - Cys - Cys - Phe - Ser - Arg - Ala - Tyr - Pro - Thr - Pro-40 - Leu - Arg - Ser - Lys - Lys - Thr - Met - Leu - Val - Gln-50 - Lys - Asn - Val - Thr - Ser - Glu - Ser - Thr - Cys - Cys-60 - Val - Ala - Lys - Ser - Thr - Asn - Arg - Val - Thr - Val-70 - Met - Gly - Gly - Phe - Lys - Val - Glu - Asn - His - Thr-80 - Ala - Cys - His - Cys - Ser - Thr - Cys - Tyr - Tyr - His-90 - Lys - Ser. Oligosaccharide side chains are attached at residues 52 and 78. In the preparations studied approximately 10 and 30% of the chains lack the initial 2 and 3 NH2-terminal residues, respectively. This sequence is almost identical with that of human luteinizing hormone (Sairam, M. R., Papkoff, H., and Li, C. H. (1972) Biochem. Biophys. Res. Commun. 48, 530-537). The amino acid sequence of the beta subunit is: Ser - Lys - Glu - Pro - Leu - Arg - Pro - Arg - Cys - Arg-10 - Pro - Ile - Asn - Ala - Thr - Leu - Ala - Val - Glu - Lys-20 - Glu - Gly - Cys - Pro - Val - Cys - Ile - Thr - Val - Asn-30 - Thr - Thr - Ile - Cys - Ala - Gly - Tyr - Cys - Pro - Thr-40 - Met - Thr - Arg - Val - Leu - Gln - Gly - Val - Leu - Pro-50 - Ala - Leu - Pro - Gin - Val - Val - Cys - Asn - Tyr - Arg-60 - Asp - Val - Arg - Phe - Glu - Ser - Ile - Arg - Leu - Pro-70 - Gly - Cys - Pro - Arg - Gly - Val - Asn - Pro - Val - Val-80 - Ser - Tyr - Ala - Val - Ala - Leu - Ser - Cys - Gln - Cys-90 - Ala - Leu - Cys - Arg - Arg - Ser - Thr - Thr - Asp - Cys-100 - Gly - Gly - Pro - Lys - Asp - His - Pro - Leu - Thr - Cys-110 - Asp - Asp - Pro - Arg - Phe - Gln - Asp - Ser - Ser - Ser - Ser - Lys - Ala - Pro - Pro - Pro - Ser - Leu - Pro - Ser-130 - Pro - Ser - Arg - Leu - Pro - Gly - Pro - Ser - Asp - Thr-140 - Pro - Ile - Leu - Pro - Gln. Oligosaccharide side chains are found at residues 13, 30, 121, 127, 132, and 138. The proteolytic enzyme, thrombin, which appears to cleave a limited number of arginyl bonds, proved helpful in the determination of the beta sequence.     

SNPs in the porcine <Emphasis Type="Italic">PPARGC1a</Emphasis> gene: Interbreed differences and their phenotypic effects

Due to its function, the peroxisome proliferative activated receptor-γ, coactivator-1α (PPARGC1A) gene is a candidate in the search for genes that may affect production traits in the pig. The purpose of this study was to screen for new SNPs in exon 8 of the porcine PPARGC1A gene and to test their possible association with production traits. Altogether 736 pigs representing five breeds Polish Landrace, n=242; Polish Large White, n=192; Hampshire, n=27; Duroc, 21; Pietrain, n=12) and synthetic line 990 (n=242) were scanned via SSCP assay. Four SNPs were found; two new ones: C/G (His338Gln) and G/A Thr359Thr), and two previously reported ones: C/A (Arg369Arg) and T/A Cys430Ser). The missense T/A and C/G SNPs demonstrated pronounced interbreed variability in terms of allele frequencies, including the exclusive presence of the C/G substitution in the Hampshire breed. The tested SNPs occurred in five putative haplotypes, and their frequency also differed substantially between breeds. The association of the SNPs with production traits was tested for G/A (Thr359Thr), C/A (Arg369Arg) and T/A (Cys430Ser) substitutions in Polish Large White, Polish Landrace and line 990. The analysis revealed only breed-specific associations. The T/A (Cys430Ser) SNP was related to the feed conversion ratio in the Polish Large White (P=0.02), and the silent G/A and C/A substitutions were respectively associated with abdominal fat in line 990 and backfat thickness in Polish Landrace (P=0.04). The combined effects of the substitutions were estimated as haplotype effects. Three significant contrasts between haplotypes were calculated, but the observed associations were again only breed-specific.     

Amino acid sequence of a protease inhibitor isolated from Sarcophaga bullata determined by mass spectrometry.

The amino acid sequence of a protease inhibitor isolated from the hemolymph of Sarcophaga bullata larvae was determined by tandem mass spectrometry. Homology considerations with respect to other protease inhibitors with known primary structures assisted in the choice of the procedure followed in the sequence determination and in the alignment of the various peptides obtained from specific chemical cleavage at cysteines and enzyme digests of the S. bullata protease inhibitor. The resulting sequence of 57 residues is as follows: Val Asp Lys Ser Ala Cys Leu Gln Pro Lys Glu Val Gly Pro Cys Arg Lys Ser Asp Phe Val Phe Phe Tyr Asn Ala Asp Thr Lys Ala Cys Glu Glu Phe Leu Tyr Gly Gly Cys Arg Gly Asn Asp Asn Arg Phe Asn Thr Lys Glu Glu Cys Glu Lys Leu Cys Leu.     

The primary structure of the β-subunit of protocatechuate 3,4-dioxygenase from Pseudomonas aeruginosa

The complete amino acid sequence of the β-subunit of protocatechuate 3,4-dioxygenase was determined. The β-subunit contained four methionine residues. Thus, five peptides were obtained after cleavage of the carboxymethylated β-subunit with cyanogen bromide, and were isolated on Sephadex G-75 column chromatography. The amino acid sequences of the cyanogen bromide peptides were established by characterization of the peptides obtained after digestion with trypsin, chymotrypsin, thermolysin, or Staphylococcus aureus protease. The major sequencing techniques used were automated and manual Edman degradations. The five cyanogen bromide peptides were aligned by means of the amino acid sequences of the peptides containing methionine purified from the tryptic hydrolysate of the carboxymethylated β-subunit. The amino acid sequence of all the 238 residues was as follows: ProAlaGlnAspAsnSerArgPheValIleArgAsp ArgAsnTrpHis ProLysAlaLeuThrPro-Asp — TyrLysThrSerIleAlaArg SerProArgGlnAla LeuValSerIleProGlnSer — IleSerGluThrThrGly ProAsnPheSerHisLeu GlyPheGlyAlaHisAsp-His — AspLeuLeuLeuAsnPheAsn AsnGlyGlyLeu ProIleGlyGluArgIle-Ile — ValAlaGlyArgValValAsp GlnTyrGlyLysPro ValProAsnThrLeuValGluMet — TrpGlnAlaAsnAla GlyGlyArgTyrArg HisLysAsnAspArgTyrLeuAlaPro — LeuAspProAsn PheGlyGlyValGly ArgCysLeuThrAspSerAspGlyTyrTyr — SerPheArg ThrIleLysProGlyPro TyrProTrpArgAsnGlyProAsnAsp — TrpArgProAla HisIleHisPheGlyIle SerGlyProSerIleAlaThr-Lys — LeuIleThrGlnLeuTyr PheGluGlyAspPro LeuIleProMetCysProIleVal — LysSerIleAlaAsn ProGluAlaValGlnGln LeuIleAlaLysLeuAspMetAsnAsn — AlaAsnProMet AsnCysLeuAlaTyr ArgPheAspIleValLeuArgGlyGlnArgLysThrHis PheGluAsnCys. The sequence published earlier in summary form (Iwaki et al., 1979, J. Biochem.86, 1159–1162) contained a few errors which are pointed out in this paper.     

Mutations in lipopolysaccharide-binding protein (LBP) gene change the susceptibility to clinical mastitis in Chinese Holstein

Mastitis is an unsolved human challenge all dairy farms facing with, which leads to immeasurable economic loss to the farmers. LBP gene plays a vital role in the innate immune recognition of Gram-negative bacterium that is a major cause of bovine clinical mastitis, but little is known about LBP mutations and their effects on cows' susceptibility to clinical mastitis. In this study, PCR-SSCP method was adopted to analyze SNPs of LBP gene in Chinese Holstein for the first time. 17 SNPs were found in the promoter core region, exon1, exon2, exon3, exon4 and exon8. The mutation g.-81C?→?T in promoter leads to an AP-2 binding site lost. Two mutations, g.11T?→?C (4 Leu?→?Ser) and g.68G?→?C (23Gly?→?Ala) in signal peptide brought about molecular secondary structural change, meanwhile, g.11T?→?C made a Big-1 domain lost, and there was an N-myristoylation site at the g.68G/C locus. The three mutations above were in complete linkage disequilibrium in allele A. In mature LBP protein, five mutations were found: g.3034G?→?A(36Asp?→?Asn), g.3040A?→?G(38Asn?→?Asp), g.3056T?→?C(43Ile?→?Thr) in allele D; g.4619G?→?A(67Ala?→?Thr) in allele F; 19975G?→?A (282Val?→?Met) in allele J. And SNPs in allele D and F were in complete linkage disequilibrium, also in which 38Asn?→?Asp and 67Ala?→?Thr influenced the protein secondary structure. Prediction of the 3-D structure shows mutations 36Asp?→?Asn, 38Asn?→?Asp and 43 Ile?→?Thr were on the concave surface of LBP protein at barrel-N, 67Ala?→?Thr was in the apolar pocket at barrel-N. Motif analysis shows 36Asp?→?Asn causes loss of a CK2 phosphorylation site, 67 Ala?→?Thr forms a new PKC phosphorylation site. And 43Ile?→?Thr, 67Ala?→?Thr made hydrophobic amino acids to be hydrophilic amino acids. Interestingly, the morbidity of AB (mixed type g.-81C/T, g.11T/C, g.68G/C), CD (mixed type g.3034G/A, g.3040A/G, g.3056T/C) and EF (mixed type g.4619G/A) genotype cows are significant higher than others in this study (P?相似文献   

Roles of Gln81 and Cys80 in catalysis by glycosylphosphatidylinositol-phospholipase C from Trypanosoma brucei.

Glycosylphosphatidylinositol-specific phospholipase C (GPtdIns-PLC) is found in the protozoan parasite Trypanosoma brucei. A region of protein sequence similarity exists between the protozoan enzyme and eubacterial phosphatidylinositol-phospholipases C. The functional relevance of Cys80 and Gln81 of GPtdIns-PLC, both in this region, was tested with a panel of mutations at each position. Gln81Glu, Gln81Ala, Gln81Gly, Gln81Lys and Gln81Leu mutants were inactive. Cleavage of GPtdIns was detectable in Gln81Asn, although the specific activity decreased 500-fold, and kcat was reduced 50-fold. Thus an amide side-chain at residue 81 is essential for catalysis by GPtdIns-PLC. Sulfhydryl reagents inactivate GPtdIns-PLC, suggesting that a Cys could be close to the enzyme active site. Surprisingly, p-chloromercuriphenyl sulfonate (p-CMPS) is significantly more potent than N-ethylmaleimide, the less bulky compound. This knowledge prompted us to test whether replacement of Cys80 with an amino acid possessing a bulky side-chain would inactivate GPtdIns-PLC: Cys80Ala, Cys80Thr, Cys80Phe, Cys184Ala, and Cys269-270-273Ser were constructed for that purpose. Cys80Phe lacked enzyme activity, while Cys80Ala, Cys80Thr and Cys269-270-273Ser retained 33 to 100% of wild-type activity. Interestingly, the Cys80Ala and Cys80Thr mutants became resistant to p-CMPS, as predicted if the sulfhydryl reagent reacted with Cys80 in the wild-type enzyme to form a cysteinyl mercurylphenylsulfonate moiety, a bulky adduct that inactivated GPtdIns-PLC, similar to the Cys80Phe mutation. We conclude that a bulky side-chain (or adduct) at position 80 of GPtdIns-PLC abolishes enzyme activity. Together, these observations place Cys80 and Gln81 at, or close to, the active site of GPtdIns-PLC from T. brucei.     

Structural and functional roles of small group-conserved amino acids present on helix-H7 in the β(2)-adrenergic receptor

Sequence analysis of the class A G protein-coupled receptors (GPCRs) reveals that most of the highly conserved sites are located in the transmembrane helices. A second level of conservation exists involving those residues that are conserved as a group characterized by small and/or weakly polar side chains (Ala, Gly, Ser, Cys, Thr). These positions can have group conservation levels of up to 99% across the class A GPCRs and have been implicated in mediating helix-helix interactions in membrane proteins. We have previously shown that mutation of group-conserved residues present on transmembrane helices H2-H4 in the β(2)-adrenergic receptor (β(2)-AR) can influence both receptor expression and function. We now target the group-conserved sites, Gly315(7.42) and Ser319(7.46), on H7 for structure-function analysis. Replacing Ser319(7.46) with smaller amino acids (Ala or Gly) did not influence the ability of the mutant receptors to bind to the antagonist dihydroalprenolol (DHA) but resulted in ~15-20% agonist-independent activity. Replacement of Ser319(7.46) with the larger amino acid leucine lowered the expression of the S319L mutant and its ability to bind DHA. Both the G315A and G315S mutants also exhibited agonist-independent signaling, while the G315L mutant did not show specific binding to DHA. These data indicate that Gly315(7.42) and Ser319(7.46) are stabilizing β(2)-AR in an inactive conformation. We discuss our results in the context of van der Waals interactions of Gly315(7.42) with Trp286(6.48) and hydrogen bonding interactions of Ser319(7.46) with amino acids on H1-H2-H7 and with structural water.     

Effects of orally administrated amino acids on myofibrillar proteolysis in chicks

We examined the effects of orally administrated amino acids on myfibrillar proteolysis in food-deprived chicks. Plasma N(tau)-methylhistidine concentration, as an index of myofibrillar proteolysis, was decreased by the administration of Glu, Gly, Ala, Leu, Ile, Ser, Thr, Met, Trp, Asn, Gln, Pro, Lys and Arg but not by Asp, Val, Phe, Tyr or His to chicks. Orally administrated Cys was fatal to chicks. These results indicate that oral Glu, Gly, Ala, Leu, Ile, Ser, Thr, Met, Trp, Asn, Gln, Pro, Lys and Arg administration suppressed myofibrillar proteolysis in chicks.