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Pepsin folding

Many extracellular proteins like immunoglobulins, protein hormones, serum albumin, pepsin, trypsin, ribonuclease, and others contain one or more indigenous disulfide bonds. For functional and structural studies of proteins, it is often necessary to cleave these disulfide bridges. Disulfide bonds in proteins are commonly reduced with small, soluble mercaptans, such as DTT, TCEP, 2-mercaptoethanol, thioglycolic acid, cysteine, etc. High concentrations of mercaptans (molar excess of 20- to 1,000-fold) are usually required to drive the reduction to completion. [Pg.97]

This ambiguity was resolved in the experiment shown in Table XL The peptide in this case represents the C-terminal sequence of the B-chain of insulin. The major products were the penta-peptide lacking the N-terminal phenylalanine and free phenylalanine indicating that hydrolysis was the major reaction. In addition, however, there was a significant amount of Phe-Phe. This dipeptide could only come from a transpeptidation involving an acyl transfer. The acyl transfer presumably proceeds via a covalent acyl intermediate. The evidence for this comes from the experiment shown in Table XII where Leu-Tyr-Leu was incubated with both porcine pepsin and penicillopepsin in the presence of a lO-fold excess of C-leucine over Leu-Tyr-Leu. The products, leucine and leucylleucine, were separated by high voltage electrophoresis and analyzed for their specific radioactivity. At most, only traces of radio-... [Pg.167]

Although these findings may apply to an experimental cortisone ulcer in animals, Hitzelberg in our laboratory obtained less definite results in man (H22, H23). Fifteen arthritic patients received 1 g prednisolone in 6 weeks. In the course of treatment, there was never an indication of peptic ulcer formation, although the output and concentration of pepsin in the basal secretion increased on the average about 2-fold. Paper electrophoresis of the dialyzed and lyophilized gastric juice, following steroid administration, frequently showed decrease of total carbohydrate... [Pg.268]


See other pages where Pepsin folding is mentioned: [Pg.520]    [Pg.14]    [Pg.150]    [Pg.258]    [Pg.48]    [Pg.211]    [Pg.224]    [Pg.169]    [Pg.3]    [Pg.322]    [Pg.288]    [Pg.246]    [Pg.621]    [Pg.325]    [Pg.183]    [Pg.193]    [Pg.195]    [Pg.55]    [Pg.196]    [Pg.10]    [Pg.92]    [Pg.141]    [Pg.188]    [Pg.501]    [Pg.621]    [Pg.150]    [Pg.335]    [Pg.335]    [Pg.69]    [Pg.86]    [Pg.1030]    [Pg.531]    [Pg.28]    [Pg.1381]    [Pg.19]    [Pg.231]    [Pg.70]    [Pg.432]    [Pg.252]    [Pg.275]    [Pg.286]    [Pg.437]    [Pg.311]    [Pg.170]   
See also in sourсe #XX -- [ Pg.500 ]




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Pepsin

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