Protease activity in single-chain prekallikrein
| Autor: | Qiufang Cheng, Bassem M Mohammed, David Gailani, Anton Matafonov, Mao-fu Sun, Ingrid M. Verhamme, Kusumam Joseph, Allen P. Kaplan, Ivan B. Ivanov, S. Kent Dickeson |
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| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Proteases Kininogen High-Molecular-Weight Proteolysis medicine.medical_treatment Immunology 030204 cardiovascular system & hematology Bradykinin Biochemistry 03 medical and health sciences 0302 clinical medicine medicine Animals Humans Blood Coagulation Kininogen Factor XII Protease medicine.diagnostic_test Chemistry Prekallikrein Cell Biology Hematology Kallikrein Trypsin Recombinant Proteins Mice Inbred C57BL HEK293 Cells 030104 developmental biology Amino Acid Substitution medicine.drug |
| Zdroj: | Blood. 135:558-567 |
| ISSN: | 1528-0020 0006-4971 |
| Popis: | Prekallikrein (PK) is the precursor of the trypsin-like plasma protease kallikrein (PKa), which cleaves kininogens to release bradykinin and converts the protease precursor factor XII (FXII) to the enzyme FXIIa. PK and FXII undergo reciprocal conversion to their active forms (PKa and FXIIa) by a process that is accelerated by a variety of biological and artificial surfaces. The surface-mediated process is referred to as contact activation. Previously, we showed that FXII expresses a low level of proteolytic activity (independently of FXIIa) that may initiate reciprocal activation with PK. The current study was undertaken to determine whether PK expresses similar activity. Recombinant PK that cannot be converted to PKa was prepared by replacing Arg371 with alanine at the activation cleavage site (PK-R371A, or single-chain PK). Despite being constrained to the single-chain precursor form, PK-R371A cleaves high-molecular-weight kininogen (HK) to release bradykinin with a catalytic efficiency ∼1500-fold lower than that of kallikrein cleavage of HK. In the presence of a surface, PK-R371A converts FXII to FXIIa with a specific activity ∼4 orders of magnitude lower than for PKa cleavage of FXII. These results support the notion that activity intrinsic to PK and FXII can initiate reciprocal activation of FXII and PK in solution or on a surface. The findings are consistent with the hypothesis that the putative zymogens of many trypsin-like proteases are actually active proteases, explaining their capacity to undergo processes such as autoactivation and to initiate enzyme cascades. |
| Databáze: | OpenAIRE |
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