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Tag: enzymes
Enzymes are proteins that act as biological catalysts, accelerating chemical reactions in living organisms. They regulate the rate at which these reactions proceed without being altered in the process. Enzymes are crucial for all aspects of cell metabolism, including the digestion of food, conservation and transformation of chemical energy, and the construction of cellular macromolecules from smaller precursors.
Enzymes work on molecules known as substrates, converting them into different molecules known as products. They increase the reaction rate by lowering its activation energy. Some enzymes can make their conversion of substrate to product occur many millions of times faster.
Enzymes are not consumed in chemical reactions, nor do they alter the equilibrium of a reaction. However, their activity can be affected by other molecules: inhibitors decrease enzyme activity, and activators increase activity. Many therapeutic drugs and poisons are enzyme inhibitors.
Enzymes also have valuable industrial and medical applications. They have assumed an increasing importance in industrial processes that involve organic chemical reactions. The uses of enzymes in medicine include killing disease-causing microorganisms, promoting wound healing, and diagnosing certain diseases.
1. Streptokinase (Ska) is a single-chain 414 amino acid protein, secreted by group A, C, and G streptococci. 2. The cysteine proteinase, SpeB, is also known as streptococcal pyrogenic erythrogenic toxin B or streptococcal cysteine proteinase. 3. Cell envelope proteinase. 4. Streptococcus secreted esRead more
1. Streptokinase (Ska) is a single-chain 414 amino acid protein, secreted by group A, C, and G streptococci.
See less2. The cysteine proteinase, SpeB, is also known as streptococcal pyrogenic erythrogenic toxin B or streptococcal cysteine proteinase.
3. Cell envelope proteinase.
4. Streptococcus secreted esterase, SsE, is an extracellular product that appears to have a role in virulence and pathogenesis, being essential for invasive infections and systemic dissemination.
5. Streptococcus pyogenes secretes two well-known hemolysins, streptolysin O and streptolysin S, which have effects on a variety of cell types.
6. Streptolysin O (SLO) is a pore-forming, cholesterol-dependent, oxygen-labile, thiol-activated cytotoxin. Similar types of hemolysins are produced by a variety of other pathogens, and the structure of SLO is similar to these other cholesterol-dependent cytolysins, but there are also some differences.
7. Streptolysin S, SLS, is the second type of hemolysin produced by S. pyogenes, and was originally extracted from streptococcal cells grown in the presence of serum, hence its name. It is a member of a family of proteins known as the thiazole/oxazole-modified microcins, which are produced by a number of pathogens that show hemolytic exotoxin activity.
8. The CAMP factor appears to be widespread among the streptococci, as it is present in groups A, B, C, G, M, P, R, and U.
9. S. pyogenes is known to produce up to four DNases as extracellular products. A potent DNase produced by the M1T1 globally disseminated clone is the bacteriophage-encoded SdaD2, and the major DNase that contributes to virulence.
10. S. pyogenes encodes proteins that are classified as hyaluronidases. These include the chromosomally-encoded hyaluronate lyase, HylA, and the bacteriophage-encoded hyaluronidases, HylP ; these phage-encoded enzymes are also hyaluronate lyases.
11. Chromosomally encoded hyaluronate lyase.
12. Bacteriophage-encoded hyaluronate lyase.
13. Streptococcal inhibitor of complement (SIC) is a 31 kDa protein found in M1 strains of S. pyogenes.
14. S. pyogenes produces a metalloprotein, superoxide dismutase (SodA), the function of which is to convert superoxide anions to oxygen and hydrogen peroxide; the hydrogen peroxide can then be detoxified by peroxidases.
15. S. pyogenes encodes a number of surface-associated, immunoglobulin-binding proteins, including M proteins, M-related proteins, and M-like proteins.
16. The immunoglobulin-degrading enzyme of S. pyogenes, IdeS, is a secreted cysteine proteinase that specifically cleaves the hinge region of IgG.
17. EndoS (endo-β-N-acetylglucosaminidase) EndoS is a large (108 kDa) endoglycosidase Ig-degrading enzyme that removes carbohydrates from immunoglobulin G in a highly specific manner.
18. Soluble M protein, M protein is a surface protein of group A streptococci, although it can be released through the action of bacterial- or host-derived proteases and can influence streptococcal virulence in that extracellular state.