Conformation of the high pH form of chymotrypsin

McConn, James; Fasman, Gerald D.; Hess, George P.

doi:10.1016/0022-2836(69)90145-4

Cited by 71 publications

(42 citation statements)

References 34 publications

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“…This proposal is broadly consistent with the results of low-resolution diffraction studies of chymotrypsinogen (129,140). The ORD and CD changes accompanying the high pH transition are similar to the differences between chymotrypsin and chymotrypsinogen at neutral pH (141 ).…”

Section: Chymotrypsinsupporting

confidence: 87%

“…It seemed likely that in the high pH form of the enzyme, and equally in the zymogen, the side chain of Asp 194 would move from its internal position to an orientation where it can reach the solvent, where it would interfere with substrate binding and evidently also destroy the bond-breaking site (55,141). The interpretation of the high resolution electron-density map of chy motrypsinogen (11) will show how much these ideas will need to be revised.…”

Section: Chymotrypsinmentioning

confidence: 99%

See 1 more Smart Citation

X-Ray Diffraction Studies of Enzymes

Blow¹,

Steitz²

1970

Annu. Rev. Biochem.

201

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Section: Chymotrypsinsupporting

confidence: 87%

Section: Chymotrypsinmentioning

confidence: 99%

X-Ray Diffraction Studies of Enzymes

Blow¹,

Steitz²

1970

Annu. Rev. Biochem.

201

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“…<J (Biltonen et al, 1965;McConn et al, 1969;Cantor and Timasheff, 1982), which was initially interpreted as reflecting changes in secondary structure. However, x-ray diffraction structures of chymotrypsinogen (Freer et al, 1970) and a-chymotrypsin (Birktoft and Blow, 1972) revealed only minor changes in the secondary structure.…”

Section: Chymotrypsinogen and Chymotrypsinmentioning

confidence: 99%

Aromatic and Cystine Side-Chain Circular Dichroism in Proteins

Woody

Dunker

1996

Circular Dichroism and the Conformational Analysis of Biomolecules

188

192

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“…Functionally, this group is presumed to regulate the concentration of the requisite active site conformation necessary for the formation of enzyme-substrate (or inhibitor) complexes. This concept has recently received additional support from crystallographic [26,27] and circular dichroism studies [28]. Deprotonation of the amino group is believed to result in movement of the amino group towards the exterior of the protein with a concomitant shift in the position of serine-195.…”

mentioning

confidence: 99%

Chymotrypsin Catalysis in the Presence of Formaldehyde. The pH-Dependence of Ester Hydrolysis

Marini

Martin

1971

Eur J Biochem

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1.The maximum steady state rate (kcat) of the a-chymotrypsin-catalyzed hydrolysis of acetyl-L-tyrosine ethyl ester a t 20" C in 0.15 M KC1 is 136 sec-l and is controlled by a group with p K 6.6. From a kJKL versus pH plot, two groups with pK' 6.6 and 8.3 are seen. I n 3.1 M formaldehyde, kcat is 16.3 sec-1 with the rate controlled by a group with p K 6.6 and the kCaJKm versus pH profile is bell-shaped with pK values of 6.4 and 8.4. 2.The active site concentration of a-chymotrypsin in water and in formaldehyde is identical. 3. The modification of chymotrypsin activity by formaldehyde is complete in less than 5 see and is completely reversible.4. Diisopropylphosphofluoridate completely inhibits a-chymotrypsin in the presence of formaldehyde although a t a slower rate. There is little or no inhibition with ~-1-tosylamido-2-phenylethyl chloromethyl ketone.5. These results lead to the conclusion that the active site has been modified with retention of catalytic activity. From a consideration of the reactivity of formaldehyde with the functional groups of the enzyme, it is suggested that the modification is the result of N-hydroxymethylation of the imidazole group(s) of a-chymotrypsin.A large body of evidence has accumulated which suggests that the mechanism of chymotrypsin catalysis proceeds via an acyl enzyme intermediate accord- During the course of some titration studies of chymotrypsin in formaldehyde, it was observed that chymotrypsin was enzymatically active in this solvent although less so than in water. It was also determined that all active sites were functional. A literature search revealed that other investigators [29,30] had also observed that formaldehyde inhibited chymotrypsin activity.

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Conformation of the high pH form of chymotrypsin

Cited by 71 publications

References 34 publications

X-Ray Diffraction Studies of Enzymes

X-Ray Diffraction Studies of Enzymes

Aromatic and Cystine Side-Chain Circular Dichroism in Proteins

Chymotrypsin Catalysis in the Presence of Formaldehyde. The pH-Dependence of Ester Hydrolysis

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