Lyase

The scientific names for these enzymes can be formed as “substrate group-lyase.” Aldolase, dehydratase, decarboxylase, and other similar terms are used to describe this enzyme. When a product’s name contains the word synthase, it indicates that the product is extremely important (for example, phosphosulfolactate synthase sulfite’s Michael addition to phosphoenolpyruvate). Both a Michael addition and an elimination addition are observed in the O-succinyl homoserine thiol -lyase (either MetY or MetZ) enzymes, which catalyze first the -elimination of O-succinyl homoserine (with succinate as a leaving group) and then the addition of sulphide to a vinyl intermediate intermediate. Initially, this particular reaction was categorised as a lyase, but it was later reclassified as a transferase after further research.

Examples of the enzyme lyase

Among the many different types of lyase are phenylalanine ammonia-lyase, citrate lyase, isocitrate lyase, hydroxynitrile, pectate lyase, argininosuccinate lyase, pyruvate formate lyase, alginate lyase, and pectin lyase, among others.

Classification

The enzyme lyases can be further subdivided into seven subclasses according to the classification of enzymes.

1.First, there are the lyases, which are enzymes that break down carbon-carbon bonds and also include decarboxylases. The second group includes aldehydes, which work by facilitating the reverse reaction of aldol condensation, as well as oxo acid lyases which are enzymes that break down a variety of 3-hydroxy acids, among other things.

2.The second one has a group of lyases, which act similarly to dehydratases in that they break carbon-oxygen bonds. Hydro-lyases, which are a subset of carbon-oxygen lyases, may aid in the cleavage of C-O bonds through the elimination of excess water. A few different carbon-oxygen lyases were shown to be beneficial in the reduction of phosphate or the elimination of alcohol from polysaccharides.

3.Lyases are enzymes that break down carbon-nitrogen bonds. Furthermore, they were capable of releasing ammonia while simultaneously producing a double ring or bond due to their high cleaving capacity. A couple of these enzymes may also be useful in the removal of an amide or amine group from a compound.

4.The fourth group contains lyases that cleave carbon-sulfur bonds and can either substitute for or eliminate hydrogen sulfide (H2S) from a process, depending on the situation.

5.The lyases of the fifth group are responsible for cleaving carbon-halide bonds, and they employ an action mechanism that allows them to eliminate hydrochloric acid from dichloro-diphenyl-trichloroethane (DDT), a synthetic pesticide, by cleaving carbon-halide bonds.

6.The bonds formed by lyases that cleave phosphorus-oxygen bonds, such as guanylyl cyclase and adenylyl cyclase, and which remove phosphate from nucleotide triphosphates, constitute the sixth group of enzymes in the cell.

Example of Lyases in Each Category

Carbon-Carbon Lyases

Carboxy-Lyases

Carboxylases include pyruvate decarboxylase, acetoacetate decarboxylase, oxaloacetate decarboxylase, and acetoacetate decarboxylase. Glutamate decarboxylase is an enzyme that breaks down glutamate. Malonyl-CoA decarboxylase, ornithine decarboxylase, and other related enzymes Phosphoribosylaminoimidazole carboxylase is an enzyme that breaks down phosphoribosylaminoimidazole. Lysine decarboxylase is an enzyme that breaks down lysine. Histidine decarboxylase is an enzyme that decarboxylates histidine. Aromatic L-amino acid decarboxylase is a type of enzyme that decarboxylates aromatic L-amino acids. Uridine monophosphate synthetase/Orotidine 5′-phosphate decarboxylase is an enzyme that synthesizes uridine monophosphate. Phosphoenolpyruvate carboxylase is an enzyme that breaks down phosphoenolpyruvate. Uroporphyrinogen III decarboxylase is an enzyme that decarboxylates uroporphyrinogen III. It is also known as pyro phosphomevalonate decarboxylase. RUBISCO, Adenosylmethionine decarboxylase and phosphoenolpyruvate carboxykinase are two enzymes that help the body break down dietary fat.

Aldehyde-Lyases:

 2-hydroxyphytanoyl-CoA-lyase, aldolase A, aldolase B, 2-hydroxyphytanoyl-CoA-lyase

Oxo-Acid-Lyases

 include 3-hydroxy-3-methylglutaryl-CoA lyase and 3-hydroxy-3-methylglutaryl-CoA lyase.

Carbon-Oxygen Lyases

Fumarase, carbonic anhydrase, Enolase (Alpha), aconitase, Enoyl-CoA hydratase/3-Hydroxyacyl ACP dehydrase, Methylglutaconyl-CoA hydratase, Tryptophan synthesis, Porphobilinogen synthase, cystathionine beta-s

Carbon-Nitrogen Lyases 

These are enzymes that break down carbon dioxide into nitrogen.

Histidine ammonia-lyase, Formiminotransferase cyclodeaminase, Serine dehydratase are examples of ammonia-lyases.

There are two amidine lyases: argininosuccinate lyase and adenylosuccinate lyase (see below).

Chemical lyases of carbon-sulfur atoms: cystathionine gamma-lyase, cystathionine-beta-lyase, and leukotriene C4 synthase.

Carbon-Halide Lyases

Dichloromethane dehalogenase and Halohydrin dehalogenase are examples of carbon-halide lyases.

GUANYL ACYLASE AND ADENYLYL CYCLASE are examples of phosphorus-oxygen lyases.

Specificity with Regard to the Substrate

Generally speaking, the specificity of a restricted substrate is considered to be a disadvantage for the commercialization of any enzyme because it severely limits the enzyme’s flexibility as an assistant in the manufacturing of the associated molecule in question. It is common to find lyases with a narrow substrate specificity, albeit this is not always the case. Although the majority of ammonia and hydratases-lyases have a very limited substrate specificity, the substrate specificity of decarboxylases, oxy nitrilases, and aldolases is substantially broader than that of the other enzymes.

It should be noted that the substrate specificity of a particular lyase changes depending on where it comes from. However, it is not stipulated as an absolute requirement for enzymes to possess unconstrained substrate specificity in order for them to be exploited commercially. Furthermore, there are numerous lyases in commercial usage that have a limited substrate spectrum.

Requirements for Co-factors

Depending on how much of an expensive cofactor is required, the enzyme’s economic potential could be severely constrained. Because the addition catalyzed by lyase does not involve the simple reduction or oxidation, cofactors are not required in significant quantities. Although many of the lyases that have been discovered so far require cofactors, these cofactors are engaged in a variety of processes such as the stability of reaction intermediates, substrate binding, substrate polarization, temporary binding of the nucleophile, and others.

The bulk of these cofactors are covalently bonded to the enzyme and are therefore not prohibitively expensive to get in large quantities. Thus, the cofactors of the lyases do not create a barrier to their commercialization because they are not toxic. The needs for cofactors for lyases varies depending on where they are derived from.

Conclusion

Lyase deficiency, also known as HMG-CoA lyase deficiency, is a rare inherited disorder that affects the metabolism of the amino acid leucine. It also prevents the body from synthesizing ketones, which are used for energy production during times when the body does not have enough food to sustain itself. Autosomal recessive inheritance may be involved, which implies that both copies of the gene in each cell are subjected to alterations in order for the illness to manifest itself.Typically, lyase deficiency symptoms manifest themselves within the first year of life and are characterised mostly by vomiting, diarrhea, dehydration, lethargy, and delayed muscle development. It is possible that during the lyase deficient episode, blood sugar concentrations will be exceedingly low or hypoglycemic, and a few hazardous molecules will build, causing the blood to become rather acidic, as is the case with diabetes.In contrast, if the disease is left untreated, it has the potential to cause convulsions, coma, respiratory difficulties, and even death. Infections, hard exercise, and other physical stresses are all likely to result in periods of lyase deficiency-related symptoms.