Cerebrospinal fluid, cathepsin

Proteases are essential for the conversion of inactive proprotein precursors into the active neuropeptides. Two main protease pathways have been elucidated for processing proneuropeptides and hormones the recently discovered cysteine protease cathepsin L with aminopeptidase B and the well-established subtilisin-like serine proteases that consist of prohormone con-vertases 1 and 2 followed by carboxypeptidase E/H. Endogenous regulators modulate these two protease pathways as endogenous peptide inhibitors, activators, and in vivo secretory vesicle proteins. Neuropeptides in CSE (cerebrospinal fluid) in neurological diseases can monitor brain nervous activity because neuropeptides represent active neurotransmission (93, 94). 

Cerebrospinal Fluid. The proteome of cerebrospinal fluid can provide clues to several neurological disorders, including Alzheimer disease, Parkinson disease, and multiple sclerosis. This study has identified five proteins involved in amyloid-beta metabolism and other metabolisms. These include apolipoprotein Al, cathepsin D, and hemopexin, which were downregulated in Alzheimer patients the transthyretin and pigment epidermal factors were elevated. 

The problems of cathepsin present in cerebrospinal fluid and other biological fluids are discussed in the appropriate chapters. 

Enzymological application of polarography was tried in the cerebrospinal fluid, the proteolytic activity being investigated after addition of inactivated serum as substrate (198). A comparison with the serum revealed the presence, in healthy subjects, of the cathepsin system in the cerebrospinal fluid, whereas in the serum two systems are found, viz., those of pepsinogen and cathepsin. The cathepsin activity in the cerebrospinal fluid is about half as high as that in the serum. In the cerebrospinal fluid of newborn infants lower values are found than in that of older children and adults. In 74 examinations no relationship with the diagnosis could be established, so that further study is necessary in this direction. 

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See also in sourсe #XX -- [ ]

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