Hemolytic streptococci proteins

Streptokinase. Streptokinase is a single-chain protein containing 415 amino acids, mol wt of 45,000 to 50,000 (261,284—286). It is produced by P-hemolytic streptococci and is not an enzyme per se. Only after streptokinase combines with plasminogen on a 1 1 basis to form a... 

Streptokinase. The fibrinolytic activity of streptokinase, isolated from strains of hemolytic Streptococci, was first demonstrated in 1933 (63). Streptokinase is a secreted protein product inasmuch as filtrates free of demonstrable bacteria were found to dissolve fibrin clots with rapidity. 

Mupirocin is not related to any of the sys-temically used antibiotics. It is an inhibitor of bacterial protein synthesis and is especially active against gram-positive aerobic bacteria, e.g. methicillin-resistant S. aureus and group A beta-hemolytic streptococci. Absorption through the skin is minimal. Intranasal application may be associated with irritation of mucous membranes. 

It is a purified preparation of bacterial protein obtained from (3 hemolytic streptococci. 

Streptokinase [strep toe KYE nase] is an extracellular protein purified from culture broths of Group C p-hemolytic streptococci. 

Streptokinase. Streptokinase (Kabikinasc. Streptase) is a catabolic 47.000-Da protein secreted by group C fi-hemolytic streptococci. It is a protein with no intrinsic enzymatic activity. Streptokinase activates plasminogen to plasmin. a proteolytic enzyme that hydrolyzes fibrin and... 

Varidase = 10 000 lU streptokinase and 2500 lU streptodornase. Streptokinase is a protein, an enzyme produced by beta-hemolytic streptococci. It has indirect fibrinolytic properties by binding with plasminogen. It is a fibrin non-specific thrombolytic. 

Fibrinolysis has recently been reviewed. In order for fibrinolysis to occur, the proenzyme plasminogen must be activated to plasmin by an activator. Several activators can be formed one from Hageman factor components after its activation, or by a tissue activator released from normal blood vessels. Urokinase is an activator considered to be limited in its function to the kidney. Streptokinase, a singlechain protein from 6-hemolytic streptococci, is an activator that has been studied for many years and has found clinical use especially in Europe. 

Is antigenic (foreign protein derived from beta-hemolytic streptococci). This causes a problem if recent past use or infection—strep antibodies may 4- activity... 

Streptokinase (SK), in spite of its name (-ase suffix), is a nonenzyme protein (mol. wt. 47,000). It is a catabolic product of group C 3-hemolytic streptococci. Unlike the real enzymes to be considered, it activates the fibrinolytic system indirectly. More recent research has shown that necessary steps require a prior formation of a 1 1 complex with plasminogen. This alters its conformation, thereby exposing an active site in the modified proenzyme. It is this modified complex that becomes the actual PA. SK is still a widely used thrombolytic agent, primarily because it is the least costly, is easy to obtain and had been in use for years before other PAs became available. 

Streptokinase is a 47-kDa protein produced by beta-hemolytic streptococci. It has no intrinsic enzymatic activity, but it forms a stable, noncovalent 1 1 complex with plasminogen. This produces a conformational change that exposes the active site on plasminogen that cleaves arginine 560 on free plasminogen molecules to form free plasmin. 

Streptokinase, an extracellular protein (415 aa, Mr 47 kDa) produced by various strains of /3-hemolytic streptococci. Streptokinase is not generally considered to be a proteolytic enzyme, but is one of the most potent exogenous activators of human plasminogen. Complexes of streptokinase with human plasminogen can hydrolytically activate other plasminogen molecules to plasmin which then dissolves blood clots alone [L. A. Schick, F. J. Castellino, Biochem. Biophys. Res. Commun. 1974, 57, 47 K. W. Jackson, J. Tang, Biochemistry 1982, 21, 6620]. 

Most bacterial cells are characterized by a tough, rigid cell wall (31). In some instances it is possible to isolate proteins from the cell surface or interior by simple extraction procedures without first breaking the cell wall. Thus M" protein can be extracted from hemolytic streptococci with i T/20 hydrochloric acid at 37°C. (Lancefield, 75) and T protein by treatment of the cells with pepsin at pH 2.5 for 6-12 hours (Lancefield and Dole, 78). Although some chemical alteration may be caused by such rather drastic procedures, M and T proteins extracted in this manner exhibit serological behavior similar to that shown in the intact cell. 

The antigenic structure of hemolytic streptococci has been extensively studied by Lancefield and her coworkers (76). It has been shown that at least two type-specific antigenic components, both probably protein in nature, are concerned with the type-specific reactions of group A hemolytic streptococci. These components have been designated M and T. In addition, the cells contain at least one species-specific protein capable of cross-reacting with pneumococci, which has been designated P (76, 144). 

M Protein of Hemolytic Streptococcus Group A. The experiments of Olarte referred to have now been published (154). Olarte has demonstrated that as much M protein may be recovered from the culture nitrates of certain strains of group A hemolytic streptococci as may be extracted by the Lancefield technique from the cells themselves. M protein from the culture filtrate may be fractionated by ammonium sulfate precipitation. Partially purified M protein prepared in this way did not prove to be a better antigen than material extracted from the cells at 37°C. with acid by the technique of Hirst and Lancefield loc. cit.) as had been hoped. There appears to be a correlation between mouse virulence and release of extracellular M protein. Only those strains which retain the M protein on the cell surface and do not release it into the supernatant are virulent for mice,... 

A general discussion of fibrinolysis is available in recent reviews.9 88,84 The oldest and most thoroughly studied fibrinolytic agent is streptokinase, a protein Isolated from hemolytic streptococci. Similar to human activator, it directly activates plasminogen to plasmln. 

SK is a single-chain 414-amino acid protein secreted by L-hemolytic group A, C and G streptococci [58]. The base for its use as a thrombolytic drug is that SK... 

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