Amino Acid Isomerases: Enzymes that catalyze either the racemization or epimerization of chiral centers within amino acids or derivatives. EC 5.1.1.Aldose-Ketose Isomerases: Enzymes that catalyze the interconversion of aldose and ketose compounds.Isomerases: A class of enzymes that catalyze geometric or structural changes within a molecule to form a single product. The reactions do not involve a net change in the concentrations of compounds other than the substrate and the product.(from Dorland, 28th ed) EC 5.Carbon-Carbon Double Bond Isomerases: Enzymes that catalyze the shifting of a carbon-carbon double bond from one position to another within the same molecule. EC 5.3.3.Peptidylprolyl Isomerase: An enzyme that catalyzes the isomerization of proline residues within proteins. EC Acids: Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Carbohydrate Epimerases: Enzymes that catalyze the epimerization of chiral centers within carbohydrates or their derivatives. EC 5.1.3.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Protein Disulfide-Isomerases: Sulfur-sulfur bond isomerases that catalyze the rearrangement of disulfide bonds within proteins during folding. Specific protein disulfide-isomerase isoenzymes also occur as subunits of PROCOLLAGEN-PROLINE DIOXYGENASE.Steroid Isomerases: Enzymes that catalyze the transposition of double bond(s) in a steroid molecule. EC 5.3.3.Cloning, Molecular: The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.Cyclophilins: A family of peptidyl-prolyl cis-trans isomerases that bind to CYCLOSPORINS and regulate the IMMUNE SYSTEM. EC 5.2.1.-Amino Acid Substitution: The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Immunophilins: Members of a family of highly conserved proteins which are all cis-trans peptidyl-prolyl isomerases (PEPTIDYLPROLYL ISOMERASE). They bind the immunosuppressant drugs CYCLOSPORINE; TACROLIMUS and SIROLIMUS. They possess rotamase activity, which is inhibited by the immunosuppressant drugs that bind to them.Tacrolimus Binding Proteins: A family of immunophilin proteins that bind to the immunosuppressive drugs TACROLIMUS (also known as FK506) and SIROLIMUS. EC 5.2.1.-Dodecenoyl-CoA Isomerase: A carbon-carbon double bond isomerase that catalyzes the movement double bond from C3 to C2 of an unsaturated acyl-CoA. The enzyme plays a key role in allowing acyl-CoA substrates to re-enter the beta-oxidation pathway.Sequence Alignment: The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Amino Acids, Essential: Amino acids that are not synthesized by the human body in amounts sufficient to carry out physiological functions. They are obtained from dietary foodstuffs.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Cyclophilin A: A 17-KDa cytoplasmic PEPTIDYLPROLYL ISOMERASE involved in immunoregulation. It is a member of the cyclophilin family of proteins that binds to CYCLOSPORINE.Ammonium Hydroxide: The hydroxy salt of ammonium ion. It is formed when AMMONIA reacts with water molecules in solution.Kinetics: The rate dynamics in chemical or physical systems.Sulfur-Sulfur Bond Isomerases: Enzymes that catalyze the transposition of a sulfur-sulfur bond. EC 5.3.4.Mutation: Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.Amino Acid Transport Systems: Cellular proteins and protein complexes that transport amino acids across biological membranes.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Recombinant Proteins: Proteins prepared by recombinant DNA technology.Glucose-6-Phosphate Isomerase: An aldose-ketose isomerase that catalyzes the reversible interconversion of glucose 6-phosphate and fructose 6-phosphate. In prokaryotic and eukaryotic organisms it plays an essential role in glycolytic and gluconeogenic pathways. In mammalian systems the enzyme is found in the cytoplasm and as a secreted protein. This secreted form of glucose-6-phosphate isomerase has been referred to as autocrine motility factor or neuroleukin, and acts as a cytokine which binds to the AUTOCRINE MOTILITY FACTOR RECEPTOR. Deficiency of the enzyme in humans is an autosomal recessive trait, which results in CONGENITAL NONSPHEROCYTIC HEMOLYTIC ANEMIA.Amino Acid Motifs: Commonly observed structural components of proteins formed by simple combinations of adjacent secondary structures. A commonly observed structure may be composed of a CONSERVED SEQUENCE which can be represented by a CONSENSUS SEQUENCE.Pentoses: A class of carbohydrates that contains five carbon atoms.Protein Structure, Tertiary: The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.Bacterial Proteins: Proteins found in any species of bacterium.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Genes, Bacterial: The functional hereditary units of BACTERIA.Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Mannose-6-Phosphate Isomerase: An enzyme that catalyzes the reversible isomerization of D-mannose-6-phosphate to form D-fructose-6-phosphate, an important step in glycolysis. EC Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Triose-Phosphate Isomerase: An enzyme that catalyzes reversibly the conversion of D-glyceraldehyde 3-phosphate to dihydroxyacetone phosphate. A deficiency in humans causes nonspherocytic hemolytic disease (ANEMIA, HEMOLYTIC, CONGENITAL NONSPHEROCYTIC). EC Weight: The sum of the weight of all the atoms in a molecule.DNA, Complementary: Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.Restriction Mapping: Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.Amino Acids, Aromatic: Amino acids containing an aromatic side chain.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Sequence Homology, Nucleic Acid: The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.Amino Acids, Branched-Chain: Amino acids which have a branched carbon chain.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Protein Folding: Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.Amino Acids, SulfurCatalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Leucine: An essential branched-chain amino acid important for hemoglobin formation.Conserved Sequence: A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.Isomaltose: A disaccharide consisting of two glucose units in an alpha (1-6) glycosidic linkage.Proline: A non-essential amino acid that is synthesized from GLUTAMIC ACID. It is an essential component of COLLAGEN and is important for proper functioning of joints and tendons.Catalytic Domain: The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.XyloseEnzyme Stability: The extent to which an enzyme retains its structural conformation or its activity when subjected to storage, isolation, and purification or various other physical or chemical manipulations, including proteolytic enzymes and heat.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Peptides: Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.Metabolic Engineering: Methods and techniques used to genetically modify cells' biosynthetic product output and develop conditions for growing the cells as BIOREACTORS.Saccharomyces cerevisiae: A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Bacillus: A genus of BACILLACEAE that are spore-forming, rod-shaped cells. Most species are saprophytic soil forms with only a few species being pathogenic.Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.Alanine: A non-essential amino acid that occurs in high levels in its free state in plasma. It is produced from pyruvate by transamination. It is involved in sugar and acid metabolism, increases IMMUNITY, and provides energy for muscle tissue, BRAIN, and the CENTRAL NERVOUS SYSTEM.Recombinant Fusion Proteins: Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.Proteins: Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.