Abstract: A recombinant microbial cell comprises at least one increased expressible enzyme activity controlling anabolic metabolism of ammonia as a nutrient source, the increased enzyme activity being an NADH-dependent activity catalysing the reaction (a) 2-oxoglutarate+NH3+NADH?glutamate+NAD or being an activity catalysing the reaction (b) 2-oxoglutarate+glutamine+NADH?2 glutamate+NAD or being an activity catalysing the reaction (c) glutamate+NH3+ATP?glutamine+ADP+Pi. The increased enzyme activity is encoded by a nucleic acid coding sequence linked to an expression signal not natively associated with the nucleic acid coding sequence and is increased as compared to the expression of the enzyme activity when the nucleic acid coding sequence is associated with its native expression signal.

Abstract: 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.

Abstract: 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.