Is insulin a protein?

In this brief guide, we will answer the query, “Is insulin a protein?” We will also discuss the role of insulin in protein metabolism, the functions of insulin, and the process of insulin secretion. Moreover, we will also talk about the consequences of low insulin production.

Is insulin a protein?

No, insulin is not considered a protein. Although insulin is essentially known as a hormone that regulates the storage of energy and the amount of glucose in the blood, it is also true that insulin is a protein made up of two chains, an A chain with 21 amino acids and a B chain with 30 amino acids, bonded by sulfur atoms.

To be more specific, insulin can be defined as a protein chain or peptide hormone. Insulin is a peptide or protein chain hormone. An insulin molecule contains 51 amino acids with a 5808 Da molecular weight. Insulin is created in the pancreas by the islets of Langerhans. 

Insulin itself is generated from proinsulin- a 74-amino-acid prohormone molecule. Proinsulin is a chemically inert hormone that is secreted in relatively small amounts under normal conditions.

What is the role of insulin in protein metabolism?

Protein is synthesized in the absence of insulin; insulin accelerates the net production of protein. Insulin affects the protein metabolism independently of the flow of glucose or amino acids into the cell, glycogen synthesis, or stimulation of high-energy phosphate production. 

These findings demonstrate dramatic intracellular effects of insulin in various tissues in the case of protein metabolism as well as pathways of glucose and fat metabolism. The action of insulin appears to be expressed mostly at the microsomal level in most tissues. Other hormones that alter protein metabolisms, such as growth or sex hormones, also function in the microsomes as well.

Insulin not only influences the protein metabolism at the above mentioned independent activities, but it also plays an important role in several additional intracellular sites. This only demonstrates that insulin has a huge impact on the activation of many metabolic activities, even the irrelevant ones.

It has to be noted that just because insulin’s initial effect on protein synthesis is independent of the immediate need for extracellular glucose or amino acids does not necessarily mean that a cell’s long-term functioning is independent. It is also recognized that in the absence of insulin, some proteins (enzymes) may be insufficient while others may be produced in excess.

What are the functions of insulin?

  • It stimulates cells in the liver, muscles, and adipose tissue to absorb glucose from the blood and convert it to glycogen, which can then be stored in the liver and muscles.
  • Insulin also inhibits fat from being used as an energy source. In the absence of insulin, or when insulin levels are low, glucose is not absorbed by body cells, and the body starts to utilize fat as an energy source.
  • Insulin also regulates amino acid synthesis by body cells and influences other physiological functions.
  • It also has several other anabolic effects throughout the body.

How is insulin secreted?

Only beta cells in the pancreas produce large amounts of insulin. It is typically secreted in reaction to increased blood glucose levels. Insulin can thus regulate blood glucose, and the body detects and responds to blood glucose increases by secreting insulin.

Other stimuli that enhance insulin release include the appearance and taste of food, nerve stimulation, and elevated blood levels of other fuel molecules such as amino acids and fatty acids.

What happens when there is low production of insulin?

Low production of insulin can result in diabetes. Since most of the major metabolic processes are regulated by insulin, insufficient production of insulin results in diabetes mellitus. Diabetes is again classified into two types: type 1 and type 2.

Type 1 diabetes occurs when the pancreatic beta cells produce no or very little insulin, and the patients of type 1 diabetes mellitus may need insulin injections for survival. 

The amount of insulin produced by pancreatic beta cells is insufficient to meet the demands of type 2 diabetes mellitus. Insulin resistance or “relative” insulin insufficiency is the common term used for this condition. These people may be treated with pharmaceuticals to lower their blood sugar levels, or they may eventually require medically administered insulin if other treatments fail to sufficiently manage blood glucose levels.


In this brief guide, we have answered the query, “Is insulin a protein?” We have also discussed the role of insulin in protein metabolism, the functions of insulin, and the process of insulin secretion. Moreover, we have also talked about the consequences of low insulin production.


What was missing from this post which could have made it better?

Leave a Comment