Summary: Zein seed storage protein
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Zein is a class of prolamine protein found in maize (corn). It is usually manufactured as a powder from corn gluten meal, though neither corn gluten meal nor zein contains gluten, that is, neither gliadin nor glutenin. Zein is one of the best understood plant proteins. Pure zein is clear, odorless, tasteless, hard, water-insoluble, and edible, and it has a variety of industrial and food uses.
Historically, zein has been used in the manufacture of a wide variety of commercial products, including coatings for paper cups, soda bottle cap linings, clothing fabric, buttons, adhesives, coatings and binders. The dominant historical use of zein was in the textile fibers market where it was produced under the name "Vicara". With the development of synthetic alternatives, the use of zein in this market eventually disappeared. By using electrospinning, zein fibers have again been produced in the lab, where additional research will be performed to re-enter the fiber market.
Zein's properties make it valuable in processed foods and pharmaceuticals, in competition with insect shellac. It is now used as a coating for candy, nuts, fruit, pills, and other encapsulated foods and drugs. In the United States, it may be labeled as "confectioner's glaze" (which may also refer to shellac-based glazes) and used as a coating on bakery products or as "vegetable protein." It is classified as Generally Recognized as Safe (GRAS) by the U.S. Food and Drug Administration.
Zein can be further processed into resins and other bioplastic polymers, which can be extruded or rolled into a variety of plastic products. With increasing environmental concerns about synthetic coatings (such as PFOA) and the current higher prices of hydrocarbon-based petrochemicals, there is increased focus on zein as a raw material for a variety of nontoxic and renewable polymer applications, particularly in the paper industry. Other reasons for a renewed interest in zein include concern about the landfill costs of plastics, and consumer interest in natural substances. There are also a number of potential new food industry applications.
Researchers at the University of Illinois at Urbana-Champaign and at William Wrigley Jr. Company have recently been studying the possibility of using zein to replace some of the gum base in chewing gum. They are also studying medical applications such as using the zein molecule to "carry biocompounds to targeted sites in the human body". There are a number of potential food safety applications that may be possible for zein-based packaging according to several researchers. A military contractor is researching the use of zein to protect MRE food packages. Other packaging/food safety applications that have been researched include frozen foods, ready-to-eat chicken, and cheese and liquid eggs. Food researchers in Japan have noted the ability of the zein molecule to act as a water barrier.
While there are numerous existing and potential uses for zein, the main barrier to greater commercial success has been its historic high cost until recently. Some believe the solution is to extract zein as a byproduct in the manufacturing process for ethanol or in new off-shore manufacture.
Alpha-prolamins are the major seed storage proteins of species of the grass tribe Andropogonea. They are unusually rich in glutamine, proline, alanine, and leucine residues and their sequences show a series of tandem repeats presumed to be the result of multiple intragenic duplication. In Zea mays (Maize), the 22 kDa and 19 kDa zeins are encoded by a large multigene family and are the major seed storage proteins accounting for 70% of the total zein fraction. Structurally the 22 kDa and 19 kDa zeins are composed of nine adjacent, topologically antiparallel helices clustered within a distorted cylinder. The 22 kDa alpha-zeins are encoded by 23 genes; twenty-two of the members are found in a roughly tandem array forming a dense gene cluster. The expressed genes in the cluster are interspersed with nonexpressed genes. Interestingly, some of the expressed genes differ in their transcriptional regulation. Gene amplification appears to be in blocks of genes explaining the rapid and compact expansion of the cluster during the evolution of maize.
Other biodegradable polymers
- Momany, Frank A.; Sessa, David J.; Lawton, John C.; Selling, Gordon W.; Hamaker, Sharon A. H.; and Willett, Julious L. "Structural Characterization of A-Zein" December 27, 2005, American Chemical Society
- Lawton, John W. "Zein: A History of Processing and Use", November 1, 2002, American Association of Cereal Chemists
- Gennadios, Aristippos"Protein-Based Films and Coatings" 2002
- Commission on Life Sciences "Biobased Industrial Products: Research and Commercialization Priorities" 2002.
- Horst, W.P. Amer Dyestuff Rep Vol. 38, 335, 1949.
- Miyoshi, T., Toyohara, H., Minematsu, H. "Preparation of ultrafine fibrous zein membranes via electrospinning", Polymer International Vol. 54, no. 8, 2005.
- Selling, G., Biswas, A., Patel, A., Walls, D., Dunlap, C., Wei, Y. "Impact of Solvent on Electrospinning of Zein and Analysis of Resulting Fibers", Macromolecular Chemistry and Physics Vol. 208, no. 9, 2007.
- Kobs, Lisa "Shining Up Appearances", Food Product Design.
- Lee, Richard "Multiple-use Corn zein-based Biodegradable Resins, Sheets, and Films are an attractive alternative to plastic", University of Illinois at Urbana-Champaign.
- Lawton Jr., J.W. "Plasticizers for Zein:their Effect on Tensile Properties and Water Absorption of Zein Films" January 12, 2004, Cereal Chemistry.
- Jabar, Anthony Jr; Bilodeau, Michael A.; Neivandt, David J.; Spender, Jonathan "Barrier Compositions and Articles Produced with the Compositions", December 29, 2005, United States Patent (pending)
- Parris, Nicholas; Sykes, Marguerite; Dickey, Leland C.; Wiles, Jack L.; Urbanik, Thomas J.; Cooke, Peter H. "Recyclable zein-coated kraft paper", Progress in paper recycling Vol. 11, no. 3, May 2002.
- McGowan B.A., Padua G.W., and Lee S-Y. "Formulation of Corn Zein Chewing Gum and Evaluation of Sensory Properties by the Time-Intensity Method", September, 2005, Journal of Food Science.
- Picklesimer, Phyllis. "Nanotechnologist Plans to Build Things with Bricklike Corn Molecules," University of Illinois at Urbana-Champaign.
- Bertrand, Kate, "Military packages put technology to the test," September 2005
- Padua, Graciela W., Rakotonirainy, Andrianaivo, and Wang, Qin "Zein-Based Biodegradable Packaging for Frozen Foods", University of Illinois at Urbana-Champaign
- Janes M.E.; Kooshesh S.; Johnson M.G. "Control of Listeria monocytogenes on the Surface of Refrigerated, Ready-to-eat Chicken Coated with Edible Zein Film" September, 2002, Journal of Food Science.
- Dawson, Paul "Packaging Films Fight Bacteria and Help the Environment" Clemson University
- Qiangxian Wu, Hiroshi Sakabe and Seiichiro Isobe "Studies on the toughness and water resistance of zein-based polymers by modification" June, 2003, National Food Research Institute, Japan.
- Core, Jim. "Corn Protein Could Reduce Ethanol Production Costs," April 15, 2002, United States Department of Agriculture Agricultural Research Service.
- Garratt R, Oliva G, Caracelli I, Leite A, Arruda P (January 1993). "Studies of the zein-like alpha-prolamins based on an analysis of amino acid sequences: implications for their evolution and three-dimensional structure". Proteins 15 (1): 88–99. doi:10.1002/prot.340150111. PMID 8451243.
- Song R, Llaca V, Linton E, Messing J (November 2001). "Sequence, regulation, and evolution of the maize 22-kD alpha zein gene family". Genome Res. 11 (11): 1817–25. doi:10.1101/gr.197301. PMC 311139. PMID 11691845.
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Zein seed storage protein Provide feedback
Zeins are seed storage proteins. They are unusually rich in glutamine, proline, alanine, and leucine residues and their sequences show a series of tandem repeats .
Garratt R, Oliva G, Caracelli I, Leite A, Arruda P; , Proteins 1993;15:88-99.: Studies of the zein-like alpha-prolamins based on an analysis of amino acid sequences: implications for their evolution and three-dimensional structure. PUBMED:8451243 EPMC:8451243
External database links
This tab holds annotation information from the InterPro database.
InterPro entry IPR002530
Alpha-prolamins are the major seed storage proteins of species of the grass tribe Andropogonea. They are unusually rich in glutamine, proline, alanine, and leucine residues and their sequences show a series of tandem repeats presumed to be the result of multiple intragenic duplication [PUBMED:8451243]. In Zea mays (Maize), the 22 kDa and 19 kDa zeins are encoded by a large multigene family and are the major seed storage proteins accounting for 70% of the total zein fraction. Structurally the 22 kDa and 19 kDa zeins are composed of nine adjacent, topologically antiparallel helices clustered within a distorted cylinder. The 22 kDa alpha-zeins are encoded by 23 genes [PUBMED:11691845]; twenty-two of the members are found in a roughly tandem array forming a dense gene cluster. The expressed genes in the cluster are interspersed with nonexpressed genes. Interestingly, some of the expressed genes differ in their transcriptional regulation. Gene amplification appears to be in blocks of genes explaining the rapid and compact expansion of the cluster during the evolution of maize.
The mapping between Pfam and Gene Ontology is provided by InterPro. If you use this data please cite InterPro.
|Molecular function||nutrient reservoir activity (GO:0045735)|
Below is a listing of the unique domain organisations or architectures in which this domain is found. More...
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We store a range of different sequence alignments for families. As well as the seed alignment from which the family is built, we provide the full alignment, generated by searching the sequence database using the family HMM. We also generate alignments using four representative proteomes (RP) sets, the NCBI sequence database, and our metagenomics sequence database. More...
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1Cannot generate PP/Heatmap alignments for seeds; no PP data available
Key: available, not generated, — not available.
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This page displays the phylogenetic tree for this family's seed alignment. We use FastTree to calculate neighbour join trees with a local bootstrap based on 100 resamples (shown next to the tree nodes). FastTree calculates approximately-maximum-likelihood phylogenetic trees from our seed alignment.
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|Seed source:||Pfam-B_181 (release 4.0)|
|Number in seed:||9|
|Number in full:||325|
|Average length of the domain:||134.90 aa|
|Average identity of full alignment:||41 %|
|Average coverage of the sequence by the domain:||97.79 %|
|HMM build commands:||
build method: hmmbuild --amino -o /dev/null HMM SEED
search method: hmmsearch -Z 23193494 -E 1000 --cpu 4 HMM pfamseq
|Family (HMM) version:||11|
|Download:||download the raw HMM for this family|
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This visualisation provides a simple graphical representation of the distribution of this family across species. You can find the original interactive tree in the More....
This chart is a modified "sunburst" visualisation of the species tree for this family. It shows each node in the tree as a separate arc, arranged radially with the superkingdoms at the centre and the species arrayed around the outermost ring.
How the sunburst is generated
The tree is built by considering the taxonomic lineage of each sequence that has a match to this family. For each node in the resulting tree, we draw an arc in the sunburst. The radius of the arc, its distance from the root node at the centre of the sunburst, shows the taxonomic level ("superkingdom", "kingdom", etc). The length of the arc represents either the number of sequences represented at a given level, or the number of species that are found beneath the node in the tree. The weighting scheme can be changed using the sunburst controls.
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There are some situations that the sunburst tree cannot easily handle and for which we have work-arounds in place.
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Some species in the taxonomic tree may not have one or more of the main eight levels that we display. For example, Bos taurus is not assigned an order in the NCBI taxonomic tree. In such cases we mark the omitted level with, for example, "No order", in both the tooltip and the lineage summary.
Unmapped species names
The tree is built by looking at each sequence in the full alignment for the family. We take the name of the species given by UniProt and try to map that to the full taxonomic tree from NCBI. In some cases, the name chosen by UniProt does not map to any node in the NCBI tree, perhaps because the chosen name is listed as a synonym or a misspelling in the NCBI taxonomy.
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Since we reduce the species tree to only the eight main taxonomic levels, sequences that are mapped to the sub-species level in the tree would not normally be shown. Rather than leave out these species, we map them instead to their parent species. So, for example, for sequences belonging to one of the Vibrio cholerae sub-species in the NCBI taxonomy, we show them instead as belonging to the species Vibrio cholerae.
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The tree shows the occurrence of this domain across different species. More...
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For all of the domain matches in a full alignment, we count the number that are found on all sequences in the alignment. This total is shown in the purple box.
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Finally, we group sequences from the same organism according to the NCBI code that is assigned by UniProt, allowing us to count the number of distinct sequences on which the domain is found. This value is shown in the pink boxes.
We use the NCBI species tree to group organisms according to their taxonomy and this forms the structure of the displayed tree. Note that in some cases the trees are too large (have too many nodes) to allow us to build an interactive tree, but in most cases you can still view the tree in a plain text, non-interactive representation. Those species which are represented in the seed alignment for this domain are highlighted.
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