What are Types of Insulin – Biosynthesis, Structure & Function

Did you know about Insulin? Or ever heard about diabetes? Diabetic people use This Hormone to maintain their blood sugar level. In some patients, sugar level is low and boosted, on the other hand high sugar level is reduced too.

Definition of Insulin

This is protein hormone that is secreted by B cell of islets of Langerhans of pancreas in response to glucose. It play very important role in metabolism. This protein is responsible for regulation of glucose metabolism. This is important anabolic hormone that target muscles, liver adipose and heart tissue. It can bind with receptors and target many tissues.

Types of Insulin

When you took, it acts to reduce the level of glucose in your blood. When glucose is at its lowest level, the effect of the insulin is said to have reached its ‘peak’. After this, the effect gradually wears off and blood glucose levels rise.

Your doctor or Credentialled Diabetes Educator will work out with you what type of insulin is right for you.

  • Fast-acting is clear in appearance, and starts to work from 1 to 20 minutes. It peaks approximately 1 hour later, and lasts from 3 to 5 hours. You must eat immediately after injecting fast-acting insulin.
  • Short-acting insulin is clear in appearance. It begins to work within half an hour, so you need to inject half an hour before eating, and it peaks at 2 to 4 hours and last for 6 to 8 hours.
  • Intermediate-acting insulin is cloudy in appearance, and has either protamine or zinc added to delay its action. It begins to work about 1 and a half hours after injecting, peaks at 4 to 12 hours and lasts for 16 to 24 hours. Before injecting, check the leaflet included in the pack for instructions on preparing the insulin.
  • Mixed insulin is cloudy in appearance and contains pre-mixed combinations of either a fast-acting or a short-acting insulin and an intermediate-acting insulin. This makes injecting easier by giving two types of insulin on one injection. This insulin can be taken before a meal to provide a stable level of insulin for some time after the meal. Before injecting, check the leaflet included in the pack for instructions on preparing the insulin.
  • Long-acting is clear in appearance. It typically has no pronounced peak and lasts for up to 24 hours. [1]

Insulin Diabetes

Insulin Diabetes type 1

In people with type 1 diabetes, the body produces little or no insulin as the cells that produce insulin have been destroyed by an autoimmune reaction in the body. This is replaced by daily injections is required.

Insulin Diabetes type 2

In people with type 2 diabetes the body produces this Hormone but the It does not work as well as it should. This is often referred to as insulin resistance. To compensate the body makes more but eventually cannot make enough to keep the balance right. Lifestyle changes can delay the need for tablets and/or to stabilize blood glucose levels. When this is required, it is important to understand that this is just the natural progression of the condition. [2]

Is Insulin Protein?

This is a protein. This is a peptide hormone having 51 amino acid and its molecular weight is 5808 Da.

Insulin structure / Chemistry of Insulin

This protein is separated from pancreas and its crystals are formed this is hetrodimeric protein.

 

In A- chain N-terminal is glycine and c- terminal is asparagine.in B- chain N-terminal is phenyl alanine and C- terminal is threonine.

Both chains are link together with s-s bond which is called Disulfide Bridge. Cys 7 and cys 20 of A chain joined with cys 7 and cys 19 of B chain.

As you can see in above diagram cys 6 and cys 11 joined together itself with s-s bond in A chain. If disulfide bond is break down with alkali or other reducing agent insulin will inactive.

Its structure exists in different polymeric form which depends on pH and temperature.

Its molecule consist of two polypeptide chain one is called A-chain and 2nd is called B-chain. Total 51 amino acids are present in its molecule. A- Chain contains 21 amino acids and b-chain contains 30 amino acids.

Molecular weight

  • Molecular weight is 5808 Da
  • By physical measurement its wt is about 12,000 to 48,000

Production of Insulin / Biosynthesis of Insulin

This is secreted by B- cell of islets of Langerhans of pancreas. Islets of Langerhans of Pancreas is Human Body part.

When we talk about its production it produces in premature form.

First pre- pro-insulin formed which is converted in to pro-insulin then finally converted in to insulin

Pre insulin has 109 amino acid.

  • Synthesis of pre pro insulin

This is produced in polysomes, which attach to rough endoplasmic reticulum membrane in B cell.

Production of pro-insulin

  • After synthesis pre pro insulin transfer to lumen of RER cisternae.an enzyme called signal peptidase split leader sequence (peptide chain consist of 23 A.A in its N- terminal) and pro insulin produce. Pro insulin has 86 Amino acids.
  • Production of insulin

Pro-insulin containing small vesicles are detached from ER and fuses with the cisternae of Golgi apparatus. Trypsin like protease acted upon on proinsuline and hydrolyses the peptide chain on both sides A and B active chain are formed and inactive C- peptide chain is liberated.

An enzyme carboxypeptidase B attack on c terminal peptide bond in to two intermediates and release two c- terminal basic amino acids  like Arg 63- Lys 62 from chain A and from chain B release Arg 31 and Arg 32 and C- peptide has 31 amino Acid which is spilt off. After cleavage of the C-peptide, these 2 pairs of basic residues are removed by the carboxypeptidase. The Cpeptide is the central portion of proinsulin, and the primary sequence of proinsulin goes in the order “B-C-A”. The resulting insulin is mature insulin is packaged in mature granules.

Functions of Insulin

The main and basic function is to control blood glucose level. This Hormone send signal to fat, muscle and liver cell to take glucose from blood. These parts took glucose from blood and a cycle continue.

If body has adequate amount of energy then Hormone signal to muscle to store glucose in the form of glycogen. Liver also store glucose in the form of glycogen but not in sufficient amount it store 5- 6 % glycogen.

If this hormone will not produce or if produce or not work properly then hypoglycemia and hyperglycemia will produce. When glucose level will high in blood then This signal to body parts to take glucose from blood to maintain the level of glucose.

Side effects of Insulin

Hypoglycemia and low blood sugar is most common example is glargine. Side effects are found also in those persons who use injection Lantus. This injection suggested by doctors in those patients who are suffering from type 1 and type II diabetes. Sever hyperglycemia leads to death. Most Common side effects are

  • Headeach
  • Weakness
  • Sweeting
  • Hunger
  • Fast heart beat
  • Fainting
  • Rapid breathing
  • Irritation
  • Body pain

Insulin Injection

Doctor suggested patients to us injection as their physician suggested. Dosage are different according to diabetes condition. Its injection is given to patient to control blood glucose level

Syringes use

Syringe which is used that should be new and clean. Injection neddle which is used for insulin that should be 12.8 mm in length. Different size of syringes are available in market

Where insulin to be inject

Abdomen

It can be inject in abdomen. Abdomen more quickly absorb insulin.

Arm

It can also inject in arm at fatty area

Thigh

Injection can also inject in thigh

Insulin Medication and Cost

  • Humulin R                                                              $ 99
  • Novolog Mix 70 / 30                                             $300
  • Lantus                                                                      $ 278
  • Humalog Mix 75 / 25                                            $ 338
  • ReliOn / Novolin 70 / 30                                     $200
  • Apidra                                                                      $423
  • Exubera                                                                    $45
  • Humalog Mix 75 / 25 KwikPen                           $ 338
  • Humulin N                                                              $300
  • Toujeo Max SoloStar                                             $295
  • Levemir                                                                    $437
  • Basaglar                                                                    $234
  • Novolin R                                                                 $24
  • Humulin U                                                               $38
  • Humulin L                                                                $300
  • Humulin 70 / 30 Pen                                             $250
  • Fiasp                                                                          $574

References

1 https://www.diabetesaustralia.com.au/insulin

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