摘要:
The invention provides customized proteases (i.e., mutant enzymes), methods of making customized proteases, as well as methods of using customized proteases. The customized proteases of the invention are derived from the known proteases. Altered transacylation reactions include the capability to perform transacylation reactions not substantially catalyzed by the known protease or the capability to perform transacylation reactions with improved yields, or both. The methods of the invention provide for customized proteases through site specific or random mutagenesis of the active site amino acids of the known proteases. The invention also provides for methods of using the customized proteases to prepare a preselected transacylation products. The preselected transacylation products produced can be modified by substitution at the N- or C-terminal with nucleophiles such as L-amino acids, D-amino acids, amino acid amides, and radioactive amino acids.
摘要:
The invention provides customized proteases (i.e., mutant enzymes), methods of making customized proteases, as well as methods of using customized proteases. The customized proteases of the invention are derived from the known proteases. Altered transacylation reactions include the capability to perform transacylation reactions not substantially catalyzed by the known protease or the capability to perform transacylation reactions with improved yields, or both. The methods of the invention provide for customized proteases through site specific or random mutagenesis of the active site amino acids of the known proteases. The invention also provides for methods of using the customized proteases to prepare a preselected transacylation products. The preselected transacylation products produced can be modified by substitution at the N-or C-terminal with nucleophiles such as L-amino acids, D-amino acids, amino acid amides, and radioactive amino acids.
摘要:
An auxiliary substance such as a label, support, or bioactive agent is attached to a protein at a site that is remote from the active site of the protein by the use of exopeptidase and a nucleophile which is an amino acid, amino acid derivative, amine or alcohol. In one embodiment, the nucleophile is attached to the carboxy terminus of a protein by catalysis with exopeptidase to form an adduct and then the adduct or its combination with a linker arm is bound to the auxiliary substance. In another embodiment, the auxiliary substance or its combination with a linker arm is bound to the nucleophile to form an intermediate substance which is then coupled by catalysis with exopeptidase to the carboxy terminus of a protein.
摘要:
According to the invention, there is provided null-LOX-1 barley and plant products produced thereof, such as malt manufactured by using barley kernels defective in synthesis of the fatty acid-converting enzyme lipoxygenase-1. Said enzyme accounts for the principal activity related to conversion of linoleic acid into 9-hydroperoxy octadecadienoic acid, a lipoxygenase pathway metabolite, which-through further enzymatic or spontaneous reactions-may lead to the appearance of trans-2-nonenal. The invention enables brewers to produce a beer devoid of detectable trans-2-nonenal-specific off flavors, even after prolonged storage of the beverage.
摘要:
According to the invention, there is provided null-LOX-1 barley and plant products produced thereof, such as malt manufactured by using barley kernels defective in synthesis of the fatty acid-converting enzyme lipoxygenase-1. Said enzyme accounts for the principal activity related to conversion of linoleic acid into 9-hydroperoxy octadecadienoic acid, a lipoxygenase pathway metabolite, which—through further enzymatic or spontaneous reactions—may lead to the appearance of trans-2-nonenal. The invention enables brewers to produce a beer devoid of detectable trans-2-nonenal-specific off-flavors, even after prolonged storage of the beverage.
摘要:
The present invention concerns a beverage containing proteins and/or peptides and is characterized in that it contains Cereal-LT and/or homologues as herein defined and/or a modified Cereal-LTP fraction obtainable from the Cereal-LTP and/or homologues by heating, boiling and/or mashing the Cereal-LTP and/or homologues in water at a pH between 3 and 7. The invention also concerns a method for preparing it and a use of a foam-forming additive.
摘要:
According to the invention, there is provided barley with total loss of functional lipoxygenase (LOX)-1 and LOX-2 enzymes, and plant products produced thereof, such as malt manufactured by using barley kernels defective in the synthesis of the fatty acid-dioxygenating enzymes LOX-1 and LOX-2. Said enzymes account for the principal activities related to dioxygenation of linoleic acid into 9- and 13-hydroperoxy octadecadienoic acid, respectively. 9-Hydroperoxy octadecadienoic acid represents a LOX pathway metabolite, which—through further enzymatic or spontaneous reactions—may lead to the appearance of trans-2-nonenal (T2N). The invention enables brewers to produce a beer having insignificant levels of stale, T2N-specific off-flavors, even after prolonged storage of the beverage.
摘要:
According to the invention, there is provided barley-derived beverages characterized by notably reduced levels of both dimethyl sulfide (DMS) and/or its precursor S-methyl-L-methionine (SMM), or lacking said compounds. In addition, the invention relates to methods for producing the above-mentioned beverages—and also to barley plants useful in the preparation of such beverages, as well as other plant products prepared from said plants. Utilization of the invention clears the way for making improved production procedures of beverages with improved taste profiles, and promises also for notable reductions in the thermal energy input for production of beer.
摘要:
According to the invention, there is provided null-LOX-1 barley and plant products produced thereof, such as malt manufactured by using barley kernels defective in synthesis of the fatty acid-converting enzyme lipoxygenase-1. Said enzyme accounts for the principal activity related to conversion of linoleic acid into 9-hydroperoxy octadecadienoic acid, a lipoxygenase pathway metabolite, which-through further enzymatic or spontaneous reactions-may lead to the appearance of trans-2-nonenal. The invention enables brewers to produce a beer devoid of detectable trans-2-nonenal-specific off flavors, even after prolonged storage of the beverage.
摘要:
A method for transamidating a peptide substrate having a P.sub.1 amino acid residue with a positively charged side chain. According to the invention, carboxypeptidase Y is modified to substitute at least one amino acid having a negatively charged side chain in an S.sub.1 subsite. Additionally, the modified carboxypeptidase Y can include substituted amino acid residues in an S.sub.1 ', S.sub.2 and/or S.sub.3 subsite to accommodate a specific peptide substrate.