Berberine Berberine is a quaternary ammonium salt from the protoberberine group of benzylisoquinoline alkaloids found in such plants as '' Berberis vulgaris'' (barberry), '' Berberis aristata'' (tree turmeric), ''Mahonia aquifolium'' (Oregon grape), '' H ...

bridge enzyme-like (BBE-like enzymes) form a subgroup of the

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

of FAD-linked oxidases (SCOPe d.58.32), structurally characterized by a typical fold observed initially for vanillyl-alcohol oxidase (VAO). This proteins are part of a multigene family (PF08031) that can be found in plants, fungi and bacteria. BBE-like enzymes family form a large subgroup that have a special C-terminal structural element adjacent to the substrate binding region. An homonym of this family is the (S)-reticuline oxidase or berberine bridge enzyme from

California poppy ''Eschscholzia californica'', the California poppy, golden poppy, California sunlight or cup of gold, is a species of flowering plant in the family Papaveraceae, native to the United States and Mexico. It is cultivated as an ornamental p ...

(''Eschscholzia californica''), the responsible of catalyzing the conversion of (S)-reticuline to (S)-scoulerine. This conversion is made by an oxidative ring closure reaction. The product of this reaction is the C-C bond and is referred to as the berberine bridge. Also, marks a branch point in the biosynthesis of benzylisoquinoline alkaloids. As mentioned above, BBE-like enzymes are in the large family of

FAD A fad or trend is any form of collective behavior that develops within a culture, a generation or social group in which a group of people enthusiastically follow an impulse for a short period. Fads are objects or behaviors that achieve short- ...

-linked oxidases. Regarding the structure of this particular family, they have a FAD binding module formed by the N- and C- terminal parts of the protein. There is a substrate binding module that, in collaboration with

isoalloxazine Isoalloxazine is the structural foundation of flavins such as riboflavin (vitamin B2) and is a heterocyclic compound. It has a tricyclic structure which means it has three interconnected rings of atoms and is a tautomer of alloxazine. The structu ...

ring of FAD, disposes the environment for efficient substrate binding and

oxidation Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate change. Oxidation is the loss of electrons or an increase in the oxidation state, while reduction is the gain of electrons or a ...

.Daniel B, Konrad B, Toplak M, Lahham M, Messenlehner J, Winkler A, Macheroux P.
"The family of berberine bridge enzyme-like enzymes: A treasure-trove of oxidative reactions"
''Archives of Biochemistry and Biophysics'' (2017), https://dx.doi.org/10.1016/j.abb.2017.06.023

Purification process

Cell cultures of ''Berberis beaniana'' (''B. beaniana),'' which in this certain experiment are taken as an example, were harvested 10–12 days, contained large amounts of proto-berberines, mainly

jatrorrhizine Jatrorrhizine is a protoberberine alkaloid found in some plant species, such as '' Enantia chlorantha'' (Annonaceae). Synonyms that may be encountered include jateorrhizine, neprotin, jatrochizine, jatrorhizine, and yatrorizine. Bioactive effect ...

. These quaternary alkaloids have a strong inhibitory effect on the BBE, so they had to be removed. In order to eliminate most of these interfering cationic substances, the enzyme solution was treated first with carboxymethyl-Sepharose and subsequently with dextrancoated charcoal. After that, the resulting solution was fractionated using standard procedures and generated, after isoelectric focusing, a single protein band in SDS gel electrophoresis. In the end, the obtained enzyme had been purified 450 times and contained 0.7% of the activity present in the crude extract at the beginning.Stevens, P.; Naotaka N.; Meinhart H.Z
Purification and characterization of the berberine bridge enzyme from ''berberis beaniana'' cell cultures
Phytochemistry, Vol. 24, No. 11, pp. 2577-2583, (1985).

Properties

The BBE-like enzyme's optimum pH is 8.9, this means it works in an alkaline medium, but the

isoelectric point The isoelectric point (pI, pH(I), IEP), is the pH at which a molecule carries no net electrical charge or is electrically neutral in the statistical mean. The standard nomenclature to represent the isoelectric point is pH(I). However, pI is also ...

of the homogeneous enzyme is located at pH 4.9, which is a rather an acid medium. This value was obtained with

isoelectric focusing Isoelectric focusing (IEF), also known as electrofocusing, is a technique for separating different molecules by differences in their isoelectric point (pI). It is a type of zone electrophoresis usually performed on proteins in a gel that takes ...

and

chromatofocusing Chromatofocusing is a protein-separation technique that allows resolution of single proteins and other ampholytes from a complex mixture according to differences in their isoelectric point The isoelectric point (pI, pH(I), IEP), is the pH at whic ...

techniques. The enzyme broad temperature range is between 40-50 degrees Celsius. The molecular weight of the protein was determined by two processes that show two different results: by SDS gel electrophoresis comes to be 54 kD, and by gel filtration on AcA 54 the enzyme corresponds to a molecular weight of 49 kD, adopting globular shape. A purification study shows that the true

molecular weight A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioch ...

is in the range of 52 ±4 kD. On the other hand, total activity decreases drastically during the stationary phase.

Known functions

BBE-like enzymes serve as a catalyzer for a wide range of reactions. All the way from two-electron oxidations as observed in (''At)''BBE-like 15 to four-electron oxidations as seen in Dbv29. BBE-like enzymes are involved in the synthesis of plenty of

isoquinoline Isoquinoline is a heterocyclic aromatic organic compound. It is a structural isomer of quinoline. Isoquinoline and quinoline are benzopyridines, which are composed of a benzene ring fused to a pyridine ring. In a broader sense, the term isoquin ...

alkaloids Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...

such as the conversion of (S)-

reticuline Reticuline is a chemical compound found in a variety of plants including '' Lindera aggregata'', ''Annona squamosa'', and ''Ocotea fasciculata'' (also known as ''Ocotea duckei''). It is based on the benzylisoquinoline structure. Reticuline is o ...

to (S)-

scoulerine Scoulerine, also known as discretamine and aequaline, is a benzylisoquinoline alkaloid (BIA) that is derived directly from (''S'')-reticuline through the action of BBE-like enzymes, berberine bridge enzyme. It is a precursor of other BIAs, notably ...

or by guiding (S)-reticuline to protoberberine, protopine, benzophenanthridine, phthalide isoquinoline or rhoeadine metabolic pathways. Research on this matter is rare since it is very complex and had never been looked into until recently. New studies reveal that BBE-like enzymes are involved in the biological synthesis of the alkaloids intermediates communesin as well as chanoclavine (I). The mechanism through which reactions are catalyzed by these BBE-like enzymes has not been found yet, but the resulting conformation of the products suggests that a similar coupling of substrate oxidation and ring formation occurs in these processes.

BBE-like enzymes in plants

BBE-like enzymes in plant physiology play a role in primary metabolism catalyzed by members of this family. The

of a variety of alcohol groups supplies a first understanding of the origin of the BBE-like enzyme family, present in reactions like oxidation of

mono Mono may refer to: Common meanings * Infectious mononucleosis, "the kissing disease" * Monaural, monophonic sound reproduction, often shortened to mono * Mono-, a numerical prefix representing anything single Music Performers * Mono (Japanese ...

and

polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with ...

s. It seems that they are present in a huge percentage of plants. A common reaction of BBE-like enzymes from plants is the oxidation of carbohydrates at the anomeric center to the appropriate

lactone Lactones are cyclic carboxylic esters, containing a 1-oxacycloalkan-2-one structure (), or analogues having unsaturation or heteroatoms replacing one or more carbon atoms of the ring. Lactones are formed by intramolecular esterification of the co ...

s. A member of these enzymes is

hexose oxidase In enzymology, a hexose oxidase () is an enzyme that catalyzes Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain un ...

(HOX) from ''

Chondrus crispus ''Chondrus crispus''—commonly called Irish moss or carrageen moss ( Irish ''carraigín'', "little rock")—is a species of red algae which grows abundantly along the rocky parts of the Atlantic coast of Europe and North America. In its fresh ...

,'' a red algae that belongs to the division of

Rhodophyta Red algae, or Rhodophyta (, ; ), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority ...

. But is more related to bacterial BBE-like enzymes than to members present in plants. Other example of carbohydrate oxidizing BBE-like enzyme is nectarin V (Nec5) from tobacco. Its function is to convert glucose to

gluconolactone Glucono-delta-lactone (GDL), also known as gluconolactone, is a food additive with the E-number E575 used as a sequestrant, an acidifier, or a curing, pickling, or leavening agent. It is a lactone of D- gluconic acid. Pure GDL is a white odo ...

. Nec5 is related with the pathogen defense system of plants, because it protects reproductive organelles. Another function of this class of enzymes in plants is Defense response homeostasis. BBE-like enzymes play a key role as oligosaccharide oxidases, reducing the activity of olygogalacturonanes (fragments of pectin) and oligocellobiose (fragments of cellulose) as

DAMPS Damage-associated molecular patterns (DAMPs) are molecules within cells that are a component of the innate immune response released from damaged or dying cells due to trauma or an infection by a pathogen. They are also known as danger-associated m ...

Medical applications

Berberine bridge enzyme (BBE) is a central enzyme in the biosynthesis of

berberine Berberine is a quaternary ammonium salt from the protoberberine group of benzylisoquinoline alkaloids found in such plants as '' Berberis vulgaris'' (barberry), '' Berberis aristata'' (tree turmeric), ''Mahonia aquifolium'' (Oregon grape), '' H ...

, a pharmaceutically important alkaloid. The enzyme itself hasn't had extensive research carried on, and has very limited, if any, specific medical application. On the other hand, berberine is highly regarded for its interactions with several diseases. Berberine has been known to influence weight loss, and this antiobesity effect may benefit all conditions related to increased body mass such as hypertension,

dyslipidemia Dyslipidemia is an abnormal amount of lipids (e.g. triglycerides, cholesterol and/or fat phospholipids) in the blood. Dyslipidemia is a risk factor for the development of atherosclerotic cardiovascular disease ( ASCVD). ASCVD includes coronary ar ...

pre-diabetes Prediabetes is a component of the metabolic syndrome and is characterized by elevated blood sugar levels that fall below the threshold to diagnose diabetes mellitus. It usually does not cause symptoms but people with prediabetes often have obesit ...

. This may reduce the likelihood of getting sedentary diseases such as

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome, a group of signs and symptoms caused by an impairment of the heart's blood pumping function. Symptoms typically include shortness of breath, excessive fatigue, ...

or other problems related to this issue. By being an

AMPK AMPK may refer to: * AMP-activated protein kinase, an enzyme * (acetyl-CoA carboxylase) kinase In enzymology, a cetyl-CoA carboxylasekinase () is an enzyme that catalyzes the chemical reaction :ATP + cetyl-CoA carboxylase\rightleftharpoons AD ...

activator like Metformin, it acts similar, affecting metabolism in a way that may reveal useful applications to treat type-2 diabetes. Overall, this alkaloid might be useful in the treatment and study of diseases like polycystic ovary syndrome (

PCOS Polycystic ovary syndrome, or PCOS, is the most common endocrine disorder in women of reproductive age. The syndrome is named after the characteristic cysts which may form on the ovaries, though it is important to note that this is a sign and ...

), some types of cancer, heart problems or

Brief history

First discovered and named by E. Rink and H. Böhm in 1974 they were isolated in cell suspension cultures of the

Papaveraceae The Papaveraceae are an economically important family of about 42 genera and approximately 775 known species of flowering plants in the order Ranunculales, informally known as the poppy family. The family is cosmopolitan, occurring in tempera ...

'' Macleaya microcarpa.''Rink E. and Böhm H.(1975)
Conversion of reticuline into scoulerine by a cell free preparation from ''Macleaya microcarpa'' cell suspension cultures
''FEBS Letters'', 49, doi: 10.1016/0014-5793(75)80794-0 Since then, many minor advancements have been made in this particular topic, but BBE-like enzymes, either for their lack of study, or the lack of clear indications that it might contain useful information for other scientific research, have yet to be fully worked on, and subsequently known at their full complexity.

References

{{Reflist, 34em Biochemistry