Paper Topic:

Insulin

Insulin

I . Introduction

Insulin is a hormone secreted by the pancreas . Insulin , a type of protein , regulates the amount of glucose (a form of sugar ) in the blood When a person has insufficient insulin the amount of sugar in the blood increases . The increase may result in diabetes mellitus , a metabolic disease . Too much insulin lowers the blood -sugar level . This may cause insulin shock , which is marked by convulsions and coma and is sometimes fatal

Insulin is prescribed in severe cases of diabetes mellitus . For medicinal purposes , most insulin

is obtained from the pancreas of cattle and hogs . The extract is mixed with zinc chloride and either of two proteins , globin or protamine . These proteins prolong into the bloodstream . Humulin is synthetic human insulin produced by a strain of bacteria created in a laboratory through a process called gene splicing . Insulin was discovered in 1921-22 by Frederick G . Banting , Charles H Best , James B Collip , and John J .R . Macleod of the University of Toronto (Banting and Macleon shared the 1923 Nobel Prize in medicine for this work . It was named insulin (from insula , Latin for island ) because it is produced by certain cells is the islets of Langerhans , small bodies in the pancreas . Humulin was first produced in 1978

The intents of this are to (1 ) know the three features of the insulin molecule that might create problems for its production in a recombinant protein expression system (2 ) figure out the features which create problems and how would you solve these problems using an Eschericia coli or Saccharomyces cerevisae expression system and (3 find out why is microbial expression over vertebrate cell expression

II . Discussion

A . Three features of the insulin molecule

To construct any protein , the cell requires a plan which contains all the information to build , modify and deliver it to the desired place This plan is called gene , which is embedded in a double stranded string along with other genes for other proteins . Altogether they form the genome of a cell which is in eukaryotes surrounded by a membrane to form the nucleus . Even in a multicellular organism the genome in different cells is always exactly the same

These genes are made of four nucleotides organised in a double helix where the adenine nucleotide always pairs with the thymine nucleotide and the cytosine nucleotide always pair with the guanine nucleotide These sequences of nucleotides which encode a gene are copied into mRNA where the thymine nucleotides are replaced by uracil nucleotides capped , polyadenylated and spliced . This process is called transcription . Transcription is highly regulated because of its direct responsibility for the concentration of a certain protein . Several types of cancer occur partly because one or more regulation mechanisms are knocked out . The reason for copying the DNA to mRNA is simply to protect the genome and when multiple copies are made a higher level of protein is achieved in a shorter period of time . After the transcription the mRNA is transferred from the...

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