Chemistry: natural resins or derivatives; peptides or proteins; – Proteins – i.e. – more than 100 amino acid residues – Plant proteins – e.g. – derived from legumes – algae or...
Reexamination Certificate
1999-11-23
2003-06-24
Bugaisky, Gabrielle (Department: 1653)
Chemistry: natural resins or derivatives; peptides or proteins;
Proteins, i.e., more than 100 amino acid residues
Plant proteins, e.g., derived from legumes, algae or...
C530S350000, C530S374000, C530S375000, C426S020000, C426S549000, C435S025000, C435S189000, C435S191000
Reexamination Certificate
active
06583271
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the use of thiol redox proteins to reduce seed protein such as cereal proteins, enzyme inhibitor proteins, venom toxin proteins and the intramolecular disulfide bonds of certain other proteins. More particularly, the invention involves use of thioredoxin and glutaredoxin to reduce gliadins, glutenins, albumins and globulins to improve the characteristics of dough and baked goods and create new doughs and to reduce cystine containing proteins such as amylase and trypsin inhibitors so as to improve the quality of feed and cereal products. Additionally, the invention involves the isolation of a novel protein that inhibits pullulanase and the reduction of that novel protein by thiol redox proteins. The invention further involves the reduction by thioredoxin of 2S albumin proteins characteristic of oil-storing seeds. Also, in particularly the invention involves the use of reduced thiol redox agents to inactivate snake neurotoxins and certain insect and scorpion venom toxins in vitro and to treat the corresponding toxicities in individuals.
This invention was made with government support under Grant Contract Nos. DCB 8825980 and DMB 88-15980 awarded by the National Science Foundation. The United States Government has certain rights in this invention.
BACKGROUND OF THE INVENTION
Chloroplasts contain a ferredoxin/thioredoxin system comprised of ferredoxin, ferredoxin-thioredoxin reductase and thioredoxins f and m that links light to the regulation of enzymes of photosynthesis (Buchanan, B. B. (1991) “Regulation of CO
2
assimilation in oxygenic photosynthesis: The ferredoxin/thioredoxin system. Perspective on its discovery, present status and future development”,
Arch. Biochem. Biophys.
288:1-9; Scheibe, R. (1991), “Redox-modulation of chloroplast enzymes. A common principle for individual control”,
Plant Physiol.
96:1-3). Several studies have shown that plants also contain a system, analogous to the one established for animals and most microorganisms, in which thioredoxin (h-type) is reduced by NADPH and the enzyme, NADP-thioredoxin reductase (NTR) according to the following:
(Florencio F. J., et al. (1988),
Arch. Biochem. Biophys.
266:496-507; Johnson, T. C., et al. (1987),
Plant Physiol.
85:446-451; Suske, G., et al. (1979),
Z. Naturforsch. C.
34:214-221). Current evidence suggests that the NADP/thioredoxin system is widely distributed in plant tissues and is housed in the mitochondria, endoplasmic reticulum and cytosol (Bodenstein-Lang, J., et al. (1989),
FEBS Lett.
258:22-26; Marcus, F., et al. (1991),
Arch. Biochem. Biophys.
287:195-198).
Thioredoxin h is also known to reductively activate cytosolic enzyme of carbohydrate metabolism, pyrophosphate fructose-6-P, 1-phosphotransferase or PFP (Kiss, F., et al. (1991),
Arch. Biochem. Biophys.
287:337-340).
The seed is the only tissue for which the NADP/thioredoxin system has been ascribed physiological activity in plants. Also, thioredoxin h has been shown to reduce thionins in the laboratory (Johnson, T. C., et al. (1987),
Plant Physiol.
85:446-451). Thionins are soluble cereal seed proteins, rich in cystine. In the Johnson, et al. investigation, wheat purothionin was experimentally reduced by NADPH via NADP-thioredoxin reductase (NTR) and thioredoxin h according to Eqs. 2 and 3.
Cereal seeds such as wheat, rye, barley, corn, millet, sorghum and rice contain four major seed protein groups. These four groups are the albumins, globulins, gliadins and the glutenins or corresponding proteins. The thionins belong to the albumin group or faction. Presently, wheat and rye are the only two cereals from which gluten or dough has been formed. Gluten is a tenacious elastic and rubbery protein complex that gives cohesiveness to dough. Gluten is composed mostly of the gliadin and glutenin proteins. It is formed when rye or wheat dough is washed with water. It is the gluten that gives bread dough its elastic type quality. Flour from other major crop cereals barley, corn, sorghum, oat, millet and rice and also from the plant, soybean do not yield a gluten-like network under the conditions used for wheat and rye.
Glutenins and gliadins are cystine containing seed storage proteins and are insoluble. Storage proteins are proteins in the seed which are broken down during germination and used by the germinating seedling to grow and develop. Prolamines are the storage proteins in grains other than wheat that correspond to gliadins while the glutelins are the storage proteins in grains other than wheat that correspond to glutenins. The wheat storage proteins account for up to 80% of the total seed protein (Kasarda, D. D., et al. (1976),
Adv. Cer. Sci. Tech.
1:158-236; and Osborne, T. B., et al. (1893),
Amer. Chem. J.
15:392-471). Glutenins and gliadins are considered important in the formation of dough and therefore the quality of bread. It has been shown from in vitro experiments that the solubility of seed storage proteins is increased on reduction (Shewry, P. R., et al. (1985),
Adv. Cer. Sci. Tech.
7:1-83). However, previously, reduction of glutenins and gliadins was thought to lower dough quality rather than to improve it (Dahle, L. K., et al. (1966),
Cereal Chem.
43:682-688). This is probably because the non-specific reduction with chemical reducing agents caused the weakening of the dough.
The “Straight Dough” and the “Pre-Ferment” methods are two major conventional methods for the manufacture of dough and subsequent yeast raised bread products.
For the Straight Dough method, all of the flour, water or other liquid, and other dough ingredients which may include, but are not limited to yeast, grains, salt, shortening, sugar, yeast nutrients, dough conditioners, and preservatives are blended to form a dough and are mixed to partial or full development. The resulting dough may be allowed to ferment for a period of time depending upon specific process or desired end-product characteristics.
The next step in the process is the mechanical or manual division of the dough into appropriate size pieces of sufficient weight to ensure achieving the targeted net weight after baking, cooling, and slicing. The dough pieces are often then rounded and allowed to rest (Intermediate Proof) for varying lengths of time. This allows the dough to “relax” prior to sheeting and molding preparations. The time generally ranges from 5-15 minutes, but may vary considerably depending on specific processing requirements and formulations. The dough pieces are then mechanically or manually formed into an appropriate shape are then usually given a final “proof” prior to baking. The dough pieces are then baked at various times, temperatures, and steam conditions in order to achieve the desired end product.
In the Pre-Ferment method, yeast is combined with other ingredients and allowed to ferment for varying lengths of time prior to final mixing of the bread or roll dough. Baker's terms for these systems include “Water Brew”, “Liquid Ferment”, “Liquid Sponge”, and “Sponge/Dough”. A percentage of flour ranging from 0-100% is combined with the other ingredients which may include but are not limited to water, yeast, yeast nutrients and dough conditioners and allowed to ferment under controlled or ambient conditions for a period of time. Typical times range from 1-5 hours. The ferment may then be used as is, or chilled and stored in bulk tanks or troughs for later use. The remaining ingredients are added (flour, characterizing ingredients, additional additives, additional water, etc.) and the dough is mixed to partial or full development.
The dough is then allowed to ferment for varying time periods. Typically, as some fermentation has taken place prior to the addition of the remaining ingredients, the time required is minimal (i.e., 10-20 min.), however, variations are seen depending upon equipment and product type. Following the second fermentation step, the dough is then treated as in the Straight Dough Method.
As used herein the term “dough mixture” describes a mixture that minimally comprises a
Buchanan Bob B.
Kobrehel Karoly
Yee Boihon C.
Bugaisky Gabrielle
Morrison & Foerster / LLP
The Regents of the University of California
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