Introduction
Edestin is characterized under the Globulin family, a 11S seed storage protein known as legumin. It is also characterized as amphoteric, meaning it can bind to acids and bases. It is encoded by the ede1A gene. Edestin has two types with each member having similar sequences. There are four forms of type 1: CsEde1A, CsEde1B, CsEde1C, and CsEde1D. Type 2 contains 3 forms: CsEde2A, CsEde2B, and CsEde2C. After an analysis of sequences was performed, a high percentage of similarity (98-99%) was revealed. [1] Edestin proteins contain essential amino acids required by humans. Amino acid composition depends on environmental factors to which the C.sativa grows and the genotypes. Estimating amino acid score can determine if the protein can satisfy human nutritional requirements. The Food and Agriculture Organization/World Health Organization have calculated the amino acid score requirement for hemp seed proteins. Hemp protein isolate contains essential amino acids, except lysine and sulfur-containing amino acids, that meet the requirements for children 2 to 5 years old compared to soy protein isolate. [2] Data has suggested that hemp protein isolate can be used as a valuable source of nutrition for infants and children. However, hemp protein isolate has poor functional properties compared to soy protein isolate. These poor functional properties are due to the formation of covalent disulfide bonds between individual proteins and subsequent aggregation at neutral or acidic pH because it is sulfhydryl free.
Function
Edestin is a legumin that functions as seed storage and is highly digestible. Edestin is considered the backbone of the DNA. Edestin is able to be metabolized in the human body to biosynthesize: hormones that regulate all processes of the body, hemoglobin which transports oxygen, carbon dioxide, and nitric acid, enzymes that catalyze and control biochemical reactions, and antibodies that fight off antigens that are invading the body. Edestin is similar to the human globular protein found in blood plasma that produces antibodies that are vital to the human immune system. This similarity also makes Edestin compatible with the human digestive system. It is assumed that this is why there have been no reported food allergies to hemp seeds. Edestin contains a high amount of glutamic acid. This acid is a neurotransmitter that aids in overcoming psychological stress. Glutamic acid also supports gut health by producing glutamine, an essential amino acid, which balances the gut microbiome. This helps make edestin highly digestible. It also supports growth in animals by being a food additive to compensate for the absence of necessary dietary proteins. Based on experiments comparing structural and functional properties, it was determined that functional properties of the hemp seed are dependent on the structural conformations as well as pH and protein concentration.[3] The protein has also been used as an antioxidant, oxidative apoptosis protective agent, antihypertensive, hydrogen peroxide-induced apoptosis protective agent, and industrial basic function ingredients.
Cannabis Sativa
Cannabis sativa, commonly known as Hemp, belongs to the Cannabaceae family. The origin of this plant has not been directly identified but most researchers agree that C. sativa originated in Asia and was introduced in Europe as a domesticated agricultural plant. This exchange is suspected to have been during the Bronze Age. This plant has a long history of cultivation and was initially a by-product of the hemp technical fiber industry. Industrial hemp is growing interest for production of hemp seeds because they are high in nutritional value and functional features. Cannabis sativa is cultivated in Asian countries, Canada, United States, Europe, and Africa. It is a sustainable and low environmental impact crop with multiple purposes. Industries that utilize C. sativa for applications include the agricultural, cosmetic, building, and pharmaceutical industries. The three main purposes for growing C. sativa are: industrial, narcotic/recreational, and medicinal. [4]
In today’s restoration methods, cultivation of female reproductive parts of the C. sativa plants contain delta-9-tetrahydrocannabinol (THC) amounts <0.3% or 0.2%. THC is a major psychoactive and toxicant phytochemical found in the hemp plant. Another phytochemical found that is non-psychoactive is CBD, cannabidiol. When cultivated for fiber, seeds, and derivatives, it is known as industrial hemp because it contains low-THC levels.[4] The presence of cannabinoids in hemp seeds can occur because of physical contact with resin secreted by the glandular trichomes located on the bracts that surround the seed. Despite the presence of cannabinoids, due to the resin contamination, hemp seed is claimed to be one of the most nutritionally complete food sources. It can be consumed as a whole (hulled seed) or as a kernel (dehulled seed). It can also be consumed through processing products such as oil, flour, and protein powder. The hemp seed is 20 to 25% proteins that are rich in essential amino acids. The proteins are located in the inner layer of the seed. Edestin constitutes 65% of the total hemp seed proteins, the remainder being albumin. When exposed to high temperatures, proteins unfold favoring protein-protein interactions. This raises many questions of the digestibility process because a protein is defined by its amino acid composition and by its digestibility and bioavailability. Protein digestibility is related to the bioavailability of its amino acids because it measures the degree of protein digestion and components. Amino acids are absorbed by the gastrointestinal tract when introduced to the human body.
Structural highlights
Edestin is a hexamer, specific to the Cannabis sativa seed, that has a molecular mass of 300 to 400 kDa. A hexamer is a polymer molecule composed of six monomers. These subunits are identical and are arranged with 32 point group symmetry. They are related to each other by an exact 3-fold axis of symmetry and 3 dyad axes perpendicular to it. Based on this structure it can be determined that the subunit’s structure creates a large channel through the center. It has been calculated that the has a diameter of 145 A and a depth of 90 A. The subunits, individually, contain a that is linked to a smaller with a disulfide bond. When translation occurs, the alpha and beta chains polypeptides are inserted into the endoplasmic reticulum. The signal peptide is then cleaved. This cleavage creates a disulfide bridge between the chains to form a pro legumin, a protein precursor. Next, three subunits link together to form a trimer in the endoplasmic reticulum and then transported to the vacuole. In the vacuole, the cleavage of the chains within the trimers signals protein maturation. Protein maturation connects two trimers together to form the hexameric protein. The trimers that form the center of the hexameric protein are beta-sheet barrels. The trimers that form the outer region of the hexameric protein consist of alpha-helices. A calcium ion ligand can be found adjacent to the Leucine 330 E residue. The is residue CA 10 CA. The ligand interaction with the Edestin protein has yet to be specified.[5]
The reference protein used is almond Pru1 protein. This protein is a homologous structure to the Edestin protein. Pru1 protein is a seed storage protein that creates required nutrition for seed germination and sprout growth. The difference between these two proteins is the Pru1 protein has been identified as an allergenic protein and Edestin has not. The structure of the Pru1 protein is similar to the Edestin protein because of the hexameric shape. Pru1 protein is a combination of two trimers while Edestin was found to be the formation of 3 trimers. The Pru1 protein also contains Calcium and Sodium Ion ligands. The Edestin protein only contains a Calcium ion ligand. [6]
