Glucose Isomerase

Isomerase belongs to a particular class of enzymes that have the ability to catalyse reactions which involves a structural rearrangement of a molecule. For example, Alanine racemase is responsible for catalysing the conversion of L-alanine into its isomeric form, which is referred to as D-alanine. Mutarotase, which is also an isomerase, is responsible for catalysing the conversion of a-D- glucose into B-D-glucose. Ligase is one of the 50 enzymes that is involved in catalysing reactions that are involved in conversion.

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Triose Phosphate

Triose Phosphate Isomerase is considered to be an enzyme that is responsible for catalysing the reversible interconversion of the triose phosphate isomers dihydroxyacetone phosphate and D-glyceraldehyde 3-phosphate. Triose Phosphate Isomerase plays a key role in glycolysis and is required for producing efficient energy. When experts started searching for TPI, they were found in almost every organism, including animals such as mammals and insects, as well as in plants, fungi and bacteria. However, there were some bacteria like ureaplasmas who do not perform glycolysis that seem to lack TPI.

Glucose Isomerase

Glucose isomerase has the ability to catalyse the reversible isomerisation of glucose into fructose as well as xylose and xylulose. It is considered an essential enzyme that is basically used in the industrial production of high fructose corn syrup (HFCS). Despite the food industry, they are also helpful and play a major role in the production of biofuel.

Phosphohexose Isomerase

Phosphohexose Isomerase, which is alternatively known as glucose phosphate isomerase, is considered to be an enzyme that is present in the human body and is encoded by the GPI gene on chromosome 19.  This gene is known for encoding a member of the glucose phosphate isomerase protein family. The protein which seems to get encoded was identified as a moonlighting protein which is based on its abilities to execute mechanistically distinct functions. Extracellularly, the encoded protein, which is also referred to as neuroleukin, has the ability to function as a neurotrophic factor that is responsible for promoting the survival of skeletal motor neurons and sensory neurons.

The encoded protein is also referred to as an autocrine motility factor which is based on the additional function as a tumour-secreted cytokine and angiogenic factor. 

Peptidyl Prolyl Isomerase

Peptidyl Prolyl Isomerase is a type of enzyme that can be found in both prokaryotes and eukaryotes that are responsible for interconverting the cis and trans isomers of peptide bonds along with the amino acid proline. Proline is known to have an unusually conformationally restrained peptide bond which exists due to its cyclic structure with its side chain being bonded to secondary amine nitrogen. Most amino acids are considered for having a strong, energetic preference which helps in supporting the trans peptide bond conformation due to steric hindrance, but the unusual structure of proline is responsible for stabilising the cis form so that both isomers can get populated under conditions that are biologically relevant. Proteins that have prolyl isomerase activity includes cyclophilin, FKBPs and parvulin. According to different studies, it is proved that larger proteins also have chances of containing prolyl isomerase domains.

Proline is considered to be unique among all the natural amino acids as they have a relatively small difference in free energy between the cis configuration of their peptide bond and the transform, which is considered to be common.

Enoyl CoA Isomerase

Enoyl CoA isomerase is also considered as one type of enzyme that is responsible for catalysing the conversion of cis-or-trans double bonds of coenzyme A (CoA) bound fatty acids, which are present at gamma-carbon (position 3) into trans double bonds, which are present at beta-carbon (position 2). The enzyme plays a key role in the metabolism of unsaturated fatty acids in beta-oxidation.

It is clear from the above paragraph that Enoyl CoA isomerase is known to be involved in beta-oxidation, which is considered to be the most frequently used pathways in fatty acid degradation of unsaturated fatty acids along with double bonds, which are present at add-numbered carbon positions. They execute it by starting to shift the double bond's position in the acyl-CoA intermediates and trying to convert it to 3-cis or trans-enoyl-CoA to 2-trans-enoyl-CoA.


In this article, we discussed some important enzymes, among which some are found in the human body, and some are not, but a maximum of them are found in every living organism. These enzymes are part of nature and help to execute a lot of activities smoothly.  They play a key role in different processes. This knowledge of various and distinct enzymes will help one in his/her career.

FAQs (Frequently Asked Questions)

1. What is Phosphomannose Isomerase?

Ans: Phosphomannose isomerase is considered as an enzyme that is responsible for facilitating the interconversion of fructose 6-phosphate (F6P) and mannose-6-phosphate (M6P). Mannose-6-phosphate isomerase also has the ability to enable the synthesis of GDP-mannose in eukaryotic organisms. By using mannose-6-phosphate isomerase, one can convert M6P into F6P and subsequently use it in several metabolic pathways that also includes glycolysis and capsular polysaccharide biosynthesis. PMI is considered to be monomeric and metallodependent upon zinc because it acts as a cofactor ligand. PMI is considered to be inhibited by erythrose 4-phosphate, mannitol 1-phosphate, and the alpha anomer of M6P, which is known to be inhibited to a lesser extent.

2. What Do You Understand By Cis-Trans Isomerase?

Ans: According to biochemistry, cis-trans isomerase is considered to be a type of isomerase that is responsible for catalysing the isomerisation of geometric isomers. Some examples of these phenomena include photoisomerase and immunophilins such as cyclophilin. This is considered to be an important isomerase among all the isomerases present in this world. They are found in a ton of enzymes and help them to execute their tasks in a smooth way without facing any difficulties and making any errors throughout the process. Isomerase is a complicated topic, but a thorough understanding of these topics can help students a lot in their future career. They will understand the importance of this topic in higher classes.