Determination of dissociation constants of crystalline α-chymotrypsin complexes

Davis, Linda A.; Hess, George P.

doi:10.1016/0022-2836(74)90572-5

Cited by 5 publications

(1 citation statement)

References 19 publications

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“…Such a displacement should affect the free energy of dimerization, if this group is indeed important in maintaining the dimeric structure. A sedimentation equilibrium experiment was performed, therefore, at pH 4.12 in the presence of 4 X 10-2 M formyl-L-phenylalanine, a concentration at which 90% of the enzyme should be liganded (Davis and Hess, 1974;Shultz et al, 1977). As shown in Table I, dimerization was greatly weakened, which is consistent with the notion that the exact position of this group plays a determining role in the strength of the self-association, although a contribution from steric interference with intermolecular contacts cannot be excluded.…”

Section: Resultsmentioning

confidence: 99%

Low pH dimerization of chymotrypsin in solution

Gorbunoff¹,

Timasheff²

1978

Biochemistry

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The mechanism of the acid dimerization of alpha-chymotrypsin in solution was reexamined using a number of chemical derivatives. Blocking of the carboxyl of Tyr-146, while that of ASP-64 remained free, eliminated completely the ability of alpha-chymotrypsin to dimerize, as did methylation of His-57. O-Acetylation of Tyr-146 reduced the dimerization constant to that of gamma-chymotrypsin, and deacetylation of the other accessible tyrosines did not affect the dimerization. It is concluded that the mechanism proposed by Aune and Timasheff [Aune, K.C., and Timasheff, S.N.(1971) Biochemistry 10, 1609-1617] for the solution dimerization which involves the electrostatic interaction between the His-57 imidazolium ring and the terminal carboxyl of Tyr-146 is still most consistent with all the experimental observations. The interactions in dilute solution may differ somewhat from those observed in crystals. In particular, the two intermolecular bridges formed by sulfate ions in crystals cannot be present in solution.

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Section: Resultsmentioning

confidence: 99%

Low pH dimerization of chymotrypsin in solution

Gorbunoff¹,

Timasheff²

1978

Biochemistry

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An NMR approach to tRNA tertiary structure in solution

Robillard

Tarr

Vosman

et al. 1977

Biophysical Chemistry

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Atomic coordinates of E. Coli tRNAy"' have been generated from the X-ray crystal structure of Yeast tRNAPhe by base substitution followed by idealization. The NMR spectrum of E. Coli tRNAy' was then calculated using these coordinates and ring current calculations. The similarity between the calculated and observed NMR spectra of this tRNA gives credence to the procedure used previously to compare the solution and X-ray crystal structure of Yeast tRNAPhe and further suggests a strong similarity between the structures of Yeast tRNAPhe and E. Coli tRNAy I a both in solution and in the crystal. The results presented here indicate that a combination of NhlR and atomic coordinates generated from a tRNA model may be a powerful procedure for determining three dimensional structure of a tRNA in solution.

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Use of N-benzoyl-L-tyrosine thiobenzyl ester as a protease substrate. Hydrolysis by alpha-chymotrypsin and subtilisin BPN.

Farmer¹,

Hageman²

1975

Journal of Biological Chemistry

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Determination of dissociation constants of crystalline α-chymotrypsin complexes

Cited by 5 publications

References 19 publications

Low pH dimerization of chymotrypsin in solution

Low pH dimerization of chymotrypsin in solution

An NMR approach to tRNA tertiary structure in solution

Use of N-benzoyl-L-tyrosine thiobenzyl ester as a protease substrate. Hydrolysis by alpha-chymotrypsin and subtilisin BPN.

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