COLLAGEN FOLDING IN PRESENCE OF CIS-TRANS ISOMERASE

折叠是蛋白质生物合成的重要步骤，因为 生物功能只有通过特定的结构才能获得。 这项提案的重点是最近发现的一个问题 酶活性称为肽基-脯氨基顺式转移酶 在体外和体内对胶原蛋白三螺旋形成的影响 活着。该活性将从猪中提纯至均一。 肾脏，并根据相对分子质量进行表征， 水动力参数、氨基酸组成、氨基末端 氨基酸序列、光谱性质和酶 运动学。根据顺式TO测定酶的活性 丁二酰丙氨酸-丙氨酸-苯丙氨酸的反式异构化反应 甲基异丙基苯基-7-酰胺 胰凝乳酶作为反式底物的裂解活性。这 酶可能有助于蛋白质的折叠，这已被证明 含脯氨酸多肽异构化对BE速率的限制 债券。为了验证这一假说，肽基-脯氨基-顺式- 反式异构酶对III型胶原体外折叠的影响 调查过了。III型胶原蛋白的复性速度 受顺式到反式多肽键异构化的限制。这个 离子强度和pH对肽基-2，4-二苯基-2，4-三甲基-4-苯基-2，4，4，4-二异氰酸酯-2，4，4-二苯基-2，4，4，4-三甲基-4，4，4，4-三甲基-4-苯基-2，4，4，4，5，5，5，5，5，5，6-二苯基-2，4，4，4，4，5，6-三甲基-4，4，4，4，5，5，5，6-三甲基-4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4，4， 研究了脯氨酰顺-反式异构酶 免疫电子显微镜细胞间定位。去看看 该酶是否积极参与体内折叠 生物合成，酶水平的相关性被研究 不同程度显影体系中的4-脯氨酸羟基酶 胶原蛋白的合成。如果折叠受损会发生什么 最近在成骨不全的病例中显示出 用单一氨基酸取代原-α中的甘氨酸残基 I型前胶原链导致前胶原分子与 降低熔化温度，增加翻译后转化率， 修饰改变了分泌速度，增加了细胞内 降解，减少胶原蛋白的产生。

Folding is an essential step of biosynthesis of proteins because biological function can only be obtained by specific structures. This proposal focuses on the question how a recently discovered enzyme activity termed peptidyl-prolyl cis-transisomerase influences the triple helix formation of collagens in vitro and in vivo. The activity is to be purified to homogeneity from pig kidneys and characterized in regard to molecular weight, hydrodynamic parameters, aminoacid composition, aminoterminal aminoacid sequence, spectroscopic properties and enzyme kinetics. Enzymatic activity is determined against the cis to trans isomerization of succinyl-Ala-Ala-Pro-Phe-4- methlycumaryl-7-amide by means of a two-step process using chymotrypsin as the trans substrate cleaving activity. This enzyme probably helps folding of protein which has been shown to be rate limited by isomerization of proline containing peptide bonds. To test this hypothesis the influence of peptidyl-prolyl cis- trans isomerase on in vitro folding of type III collagen is investigated. Refolding of type III collagen was shown to be rate limited by cis to trans isomerization of peptide bonds. The influence of ionic strength and pH on the kinetics of peptidyl- prolyl cis-trans isomerase is investigated as well as the intercellular localization by immunoelectronmicroscopy. To see whether the enzyme is actively involved in in vivo folding during biosynthesis, the enzyme level is investigated for correlation with 4-prolyl hydroxylase in a developing system with varying degrees of collagen synthesis. What happens if folding is impaired has been shown recently in cases of Osteogenesis Imperfecta where a single aminoacid substitution for a glycine residue in the pro alpha 1 chain of type I procollagen leads to procollagen molecules with decreased melting temperature, increased posttranslational, modification altered rate of secretion, increased intracellular degradation, and decreased collagen production.