The present disclosure provides uses of genetically engineered attenuated Salmonella typhimurium strain VNP20009-M in preventing and treating cancer metastasis. The genetically engineered strain VNP20009-M is targeted to cancer cells and has a significant effect of inhibiting metastasis and growth. VNP20009-M can be used to prepare medicaments for the prevention and treatment of tumor metastasis.

The present invention provides engineered methionine gamma lyase polypeptides and compositions thereof. The engineered methionine gamma lyase polypeptides have been optimized to provide improved thermostability, protease stability, and stability under a range of pH conditions, including acidic (pH<7) conditions. The present invention also relates to the use of the compositions comprising the engineered methionine gamma lyase polypeptides for therapeutic purposes.

The present disclosure provides recombinant bacterial cells that have been engineered with genetic circuitry which allow the recombinant bacterial cells to sense a patient's internal environment and respond by turning an engineered metabolic pathway on or off. When turned on, the recombinant bacterial cells complete all of the steps in a metabolic pathway to achieve a therapeutic effect in a host subject. These recombinant bacterial cells are designed to drive therapeutic effects throughout the body of a host from a point of origin of the microbiome. Specifically, the present disclosure provides recombinant bacterial cells that comprise an amino acid catabolism enzyme, e.g., a methionine catabolism enzyme for the treatment of diseases and disorders associated with amino acid metabolism, including homocystinuria, in a subject. The disclosure further provides pharmaceutical compositions and methods of treating disorders associated with amino acid metabolism, such as homocystinuria.

A composition and method for lowing serum and plasma levels of methionine by oral administration. The composition includes a recombinant methioninase enzyme and a cofactor (pyridoxal-L-phosphate). Methods of use describe methods for treatment of cancer, including malignant melanoma, by oral administration of the methioninase composition. Methods for chronic suppressive therapy of melanoma and other cancers are described. Because reduction of plasma methionine levels is effective in treating other conditions, including diabetes and conditions associated with aging, the use of the methods described herein includes treatment of these and other conditions.

The present disclosure provides host cells, e.g., bacterial cells, that comprise a methionine decarboxylase enzyme for the treatment of diseases and disorders associated with methionine metabolism in a subject. The disclosure further provides pharmaceutical compositions and methods of treating disorders associated with methionine metabolism, such as homocystinuria.

Shielding enzymes are made by modifying the enzyme surface with silica precursors and then depositing silica to a desired thickness while retaining biological activity of the enzyme.

The present invention relates to the treatment of respiratory viral infections, including those caused by coronaviruses.

The present invention provides an engineered cell, such as a T-cell, which expresses a chimeric antigen receptor (CAR) or an engineered T-cell receptor (TCR) and one or more enzymes which, when secreted or expressed at the cell surface causes depletion of a molecule extracellular to the engineered cell; wherein said molecule is selected from: an amino acid; a nucleotide or nucleoside; or a lipid.

The current invention discloses a genetically engineered bacterium used for the treatment of breast cancer. The said bacterium is attenuated Salmonella typhimurium VNP20009 with cloned L-methioninase gene. The method for constructing this genetically engineered bacterium and the application thereof are also disclosed herein. In the current invention, our biologic drug for the treatment of breast cancer is a type of safe, non-toxic new drug with anti-tumor activity. It can highly express methioninase through recombinant DNA technology using attenuated Salmonella typhimurium VNP20009 as a carrier, which has a strong anti-tumor activity and can meet the needs. The preparation method is simple and easy to operate, showing good application prospect.

Embodiment of the present invention discloses a kind of methionine lyase and its encoding gene and biosynthetic method. According to the present invention, the gene encoding methionine lyase as shown in SEQ ID No. 1 is separated from the genome of C. rosea. Embodiment of the present invention further provides an efficient biosynthetic method of methionine lyase, comprising: (1) cloning gene (shown in SEQ ID No. 1) encoding methionine degradation enzyme into a yeast expression vector to construct recombinant yeast expression vector; (2) transforming the recombinant yeast expression vector into Saccharomyces cerevisiae to obtain expression strain; (3) inducing the expression strain to express the methionine lyase, collecting induced strains, purifying expressed recombinant methionine lyase. Purity of recombinant methionine lyase prepared according to the present invention is above 90%, and its efficiency of degradating methionine can reach 0.53±0.0030 μM MTL.Math.h.sup.−1.Math.mg protein.sup.−1.