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Articles |
1
Clinical Pathology Department, National Institutes of Health, Bldg. 10, Room 2C-407, 10 Center Dr., Bethesda, MD 20892-1508.
2
Department of Pediatrics, Washington University School
of Medicine, St. Louis, MO 63110.
a Author for correspondence. Fax 301-402-1885; e-mail
ghortin{at}cc.nih.gov.
Background: Proteinase activities are often measured using chromogenic substrates that are much smaller than physiological substrates.
Methods: The hydrodynamic size of macromolecular substrates
(macrosubstrates) prepared by linking small chromogenic substrates to
polyethylene glycol was determined by gel filtration. Efficiency of
macrosubstrate cleavage by proteinases and
2-macroglobulin-proteinase complexes was monitored
spectrophotometrically.
Results: Macrosubstrates had hydrodynamic radii of
20 Å,
similar to proteins with a molecular weight of 18 000.
Different macrosubstrates served as efficient substrates for
chymotrypsin, trypsin, and thrombin. Linking small substrates to a
polymer variably affected substrate efficiency, with the impact on
activity ranging from a 60-fold decrease to a 30-fold increase.
Proteinases complexed with
2-macroglobulin had
10-fold lower activity vs macrosubstrates than small substrates.
Conclusions: Macrosubstrates are efficient substrates that allow
decreased measurement of sterically hindered proteinase
molecules such as
2-macroglobulin-proteinase complexes.
Thus, macrosubstrates may provide more accurate functional assays of
proteinases such as coagulation factors.
The following articles in journals at HighWire Press have cited this article:
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D. Roche, A. Mesner, M. Al Nakib, F. Leonard, and P. Beaune Automated Determination of Serum {alpha}1-Antitrypsin by Antitryptic Activity Measurement Clin. Chem., March 1, 2009; 55(3): 513 - 518. [Abstract] [Full Text] [PDF] |
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