Stobiecka A. Acrylamide-quenching of Rhizomucor miehei lipase.
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2005;
80:9-18. [PMID:
15963433 DOI:
10.1016/j.jphotobiol.2005.02.002]
[Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2004] [Revised: 02/11/2005] [Accepted: 02/14/2005] [Indexed: 10/25/2022]
Abstract
Steady-state and time-resolved fluorescence-quenching measurements have been performed to study multitryptophan lipase from filamentous fungus Rhizomucor miehei. Using the steady-state acrylamide fluorescence quenching data and the fluorescence-quenching-resolved-spectra (FQRS) method, the total emission spectrum of native ("closed-lid") lipase has been decomposed into two distinct spectral components accessible to acrylamide. According to FQRS analysis, more quenchable component has a maximum of fluorescence emission at about 352 nm whereas less quenchable component emits at about 332 nm. The redder component participates in about 60-64% of the total lipase fluorescence and may be characterized by the dynamic and static quenching constants equal to K(1) = 3.75 M(-1) and V(1) = 1.12 M(-1), respectively. The bluer component is quenchable via dynamic mechanism with K(2) = 1.97 M(-1). Significant difference in the values of acrylamide bimolecular rate quenching constants estimated for redder and bluer component (i.e., k(q) = 1.2 x 10 (9) M(-1)s (-1) vs. k(q) = 4.3 x 10(8) M(-1) s(-1), respectively), suggests that tryptophan residues in fungal lipase are not uniformly exposed to the solvent.
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