Role of the tryptophan fluorescent state in the ultraviolet-induced inactivation of $beta$-trypsin

Journal Article · Thu Nov 01 04:00:00 EST 1973 · Photochem. Photobiol., v. 18, no. 5, pp. 393-402

DOI:https://doi.org/10.1111/j.1751-1097.1973.tb06439.x· OSTI ID:4344447

Sellers, D R; Ghiron, C A

Stern-Volmer quenching constants for BETA -trypsin at pH 3 were determined for fluorescence quenching by histidine, acrylamide, and nitrate ion. A modified Stern-Volmer plot STALehrer, Biochem, l0,3254, (1971)! was employed to show that all of the fluorescent tryptophanyl residues of BETA -trypsin were equaily susceptible to quenching by acrylamide at pH 3 when the enzyme was either in its native conformation or denatured in 6M guanidine hydrochloride (GuHCl). Fluorescence lifetime measurements indicated that acrylamide quenched BETA - trypsin fluorescence by a purely collisional mechanism. Solvation of tryptophanyl residues of the protein was maximal at 2.5M GuHCl, as monitored by fluorescence emission wavelength. Investigations of the ultraviolet-induced inactivation of BETA -trypsin at 295 nm were performed in the presence of acrylamide at pH 3. The quantum yields for enzyme inactivation and indole destruction (determined using the PDAB reagent) were unchanged upon depopulation of the fluorescent state by 65%, whether the enzyme was in its native conformation or denatured by 6M GuHCl. It is concluded that the fluorescent state of tryptophanyl residues of BETA -trypsin is not involved in enzyme inactivation or tryptophan destruction. (auth)

• Research Organization: Univ. of Missouri, Columbia
• NSA Number: NSA-29-015836
• OSTI ID: 4344447
• Journal Information: Photochem. Photobiol., v. 18, no. 5, pp. 393-402, Journal Name: Photochem. Photobiol., v. 18, no. 5, pp. 393-402; ISSN PHCBA
• Country of Publication: United Kingdom
• Language: English

Related Subjects

*TRYPSIN-- INACTIVATION
*TRYPTOPHAN-- BIOLOGICAL RADIATION EFFECTS
ACRYLAMIDE
ANIONS
CARBONIC ACID DERIVATIVES
DILUTION
FLUORESCENCE
HETEROCYCLIC COMPOUNDS
HISTIDINE
HYDROCHLORIC ACID
N48110* --Life Sciences--Radiation Effects on Biochemicals-- In-Vitro
NITRATES
PH VALUE
PHOTON BEAMS
RESPONSE MODIFYING FACTORS
SOLUTIONS
SOLVATION
ULTRAVIOLET RADIATION