论文代写：胰岛素的作用
不同生物的胰岛素在结构上有不同。人类胰岛素由51个氨基酸组成，分子量为58.08 KDa。它是由两个链α和β与二硫键形成胰岛素二聚体。它是由胰腺β细胞合成的一种称为前胰岛素的多肽，它包含一个24种氨基酸信号肽，负责引导它到粗糙的内质网，在那里它被裂解形成胰岛素。胰岛素通过细胞内肽酶和ex蛋白酶E的作用转化为成熟的胰岛素。胰高血糖素是一种29种氨基酸分解激素。它是由一个160个氨基酸前体的乳沟合成的。与胰岛素相似，前胰高血糖素在粗面内质网(2)中转化为高血糖素，然后由蛋白酶的解理作用转化为成熟的胰高血糖素。胰高血糖素的分泌是由血糖水平和胰岛素调节的。当血糖水平或胰岛素水平升高时，胰高血糖素分泌抑制。此外，某些激素，如儿茶酚胺和皮质醇会刺激胰高血糖素的分泌。胰岛素和胰高血糖素在其作用后通过不同的途径被降解。
论文代写：胰岛素的作用
Insulin of different organism differs in their structure. Human insulin consists of 51 amino acids with molecular weight of 58.08 KDa. It is composed of two chains α and β which are linked by disulphide bond to form insulin dimer. It is synthesised from beta cells of pancreas as a single polypeptide known as preinsulin which contains a 24 amino acid signal peptide responsible for directing it to rough endoplasmic reticulum where it is cleaved to form proinsulin. proinsulin is converted into mature insulin by the action of cellular endopeptidases and exoproteasecarboxypeptidase E.Glucagon is a 29 amino acid catabolic hormone. It is synthesised by alpha cells of pancreas by the cleavage of a 160 amino acid precursor known as preproglucagon. Similar to insulin, preglucagon is converted into proglucagon at rough endoplasmic reticulum (2). Proglucagone is then converted into mature glucagon by proteolytic cleavage. The secretion of glucagon is regulated by both blood glucose level and insulin. When, blood glucose level or insulin level increases, glucagon is secretion is inhibited. In addition, certain hormones such as catecholamines and cortisol stimulate the glucagon secretion.Both insulin and glucagon is degraded through different pathways after their action.
