Specificity studies on retroviral proteinase from myeloblastosis-associated virus

The specificity of the p15 proteinase of myeloblastosis-associated virus (MAV) was tested with nonviral high molecular weight substrates and with synthetic peptides. Peptides with sequences spanning known cleavage sites in viral polyproteins of Rous sarcoma virus (RSV) and avian leukemia viruses, as...

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Bibliographic Details
Published in:Biochemistry (Easton) 1991-01, Vol.30 (14), p.3432-3443
Main Authors: Strop, P, Konvalinka, J, Stys, D, Pavlickova, L, Blaha, I, Velek, J, Travnicek, M, Kostka, V, Sedlacek, J
Format: Article
Language:English
Subjects:
Michaelis-Menten parameters
peptide synthesis
substrate specificity
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Summary:The specificity of the p15 proteinase of myeloblastosis-associated virus (MAV) was tested with nonviral high molecular weight substrates and with synthetic peptides. Peptides with sequences spanning known cleavage sites in viral polyproteins of Rous sarcoma virus (RSV) and avian leukemia viruses, as well as in BSA and HSA, were synthesized, and the rate of their cleavage by the MAV proteinase was compared. The difference between the specificity of the p15 proteinase and that of the HIV-1 proteinase mostly pertains to position P2' of the substrate, where bulkier side chains are accepted by the HIV-1 proteinase. A good chromogenic substrate for the MAV and RSV proteinases was developed and used to further characterize the MAV proteinase activity with respect to ionic strength and pH. The activity of the proteinase is strongly dependent on ionic strength and pH. Both the k sub(cat) and K sub(m) values contribute to a higher cleavage efficiency at higher salt concentrations and show a bell-shaped pH dependence curve with a sharp maximum at pH 5.5 (k sub(cat)) and 6.5 (K sub(m)).
ISSN:0006-2960