ENZYME CATALYSIS OF PROLINE ISOMERIZATION IN CRO F58W.Chemistry and Chemical Engineering ENZYME CATALYSIS OF PROLINE proline (prō`lēn), organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein. ISOMERIZATION isomerization /isom·er·iza·tion/ (i-som?er-i-za´shun) the process whereby any isomer is converted into another isomer, usually requiring special conditions of temperature, pressure, or catalysts. IN CRO F58W Melva T. [James.sup.*], Ibrahim A. Al-Duraibi, and Michael C. Mossing, University of Mississippi The University of Mississippi, also known as Ole Miss, is a public, coeducational research university located in Oxford, Mississippi. Founded in 1848, the school is composed of the main campus in Oxford and three branch campuses located in Booneville, Tupelo, and Southaven. , University, MS 38677 SlyD is a cytoplasmic peptidyl-prolyl cis-trans isomerase (PPIase) which is harvested from overexpressing strains of E. coli. This PPIase is used as a catalyst to enhance the rate of proline isomerization in the spontaneous refolding of the substrate Cro F58W. Cro, a small regulatory protein of 66 amino acid residues per subunit, has slow folding kinetics. We hypothesize that this rate is dominated by proline isomerization. The single tryptophan tryptophan (trĭp`təfăn), organic compound, one of the 20 amino acids commonly found in animal proteins. Only the l-stereoisomer appears in mammalian protein. of Cro F58W is preceded by a cis-prolyl peptide bond in the native structure, Upon refolding a hyper fluorescent species is formed which decays with a rate characteristic of proline isomerization. When acid denatured de·na·ture tr.v. de·na·tured, de·na·tur·ing, de·na·tures 1. To change the nature or natural qualities of. 2. CroF58W is mixed with neutral buffer containing SlyD, the rate enhancement of CroF58W fluorescence change shows a linear dependence on SlyD concentration in the refolding buffer. SlyD concentrations as low as 0.5 [micro]M, give a significant rate increase compared to the uncatalyzed reaction (k = 0.00606 [s.sup.-1]). |
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