1974
DOI: 10.1159/000459448
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Activation of α-Amylase by Protein and Detergents1

Abstract: Optimal salt concentration for α-amylase hydrolysis of the PHADEBAS starch substrate was 50 mmol/1 NaCl, and 50 mmol/1 phosphate buffer (pH 7.0). Under these conditions, 7 μmol/l albumin increased the activity of the enzyme 1.3-fold. The degree of activation was shown to depend on pH. Activation was greatest in the more acid region. At pH 5.4 with 7 μmol/1 albumin, there was a 6-fold increase in activity over the control. The degree of activation fell to 2-fold at pH 6.0. A similar trend in activation versus p… Show more

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Cited by 17 publications
(8 citation statements)
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References 10 publications
(17 reference statements)
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“…It can be seen that Vmax is increased (1.43-fold), with no apparent effect on Km. A similar result was obtained with taurodeoxycholate [14]. a-Amylase hydrolysis of soluble starch was not stimulated by these bile salts.…”
Section: Resultssupporting
confidence: 84%
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“…It can be seen that Vmax is increased (1.43-fold), with no apparent effect on Km. A similar result was obtained with taurodeoxycholate [14]. a-Amylase hydrolysis of soluble starch was not stimulated by these bile salts.…”
Section: Resultssupporting
confidence: 84%
“…All reagents were Analar except the following : cholic acid, deoxycholic acid, taurochenodeoxycholic acid, chenodeoxycholic acid, lithocholic acid and bovine albumin (fraction V), which were purchased from Sigma Chemical Co., London. Sodium taurocholate, purchased from Hopkins and Williams, was purified by the method of Norman [12], Phadebas tablets, obtained from Pharmacia, London, were used as substrate, having been washed free of buffer salts as previously described [14], The starch fraction (molecular weight 4,800) was prepared from soluble starch 'nach Zulkowsky' (E. Merck, Darmstadt) by dialysis and fractional ultrafiltration on Amicon membranes. The molecular size was estimated on a calibrated Sephadex G-100 column.…”
Section: Methodsmentioning
confidence: 99%
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“…Because of no ethanol-induced ·-amylase secretion via high-affinity receptors, a negativefeedback action of PKC on such a secretion was not possible and could not be prevented by PKC inhibition, contrary to suboptimal CCK-8 stimulation. Moreover, the two higher ethanol concentrations were not able to elicit an ·-amylase secretion in addition to that induced by PMA, whereas they induced significant secretions in the Siegmund/Lüthen/Kunert/Weber presence of only the PMA solvent DMSO (4 g/l ethanol elicited a significant secretion in this case, in contrast to experiments with GF, probably because of the shorter pre-incubation, a stabilizing effect of DMSO or/and a slight activation of ·-amylase by DMSO [44]). These findings agree with the results of Mironov and Hermann [22], who concluded from their experiments with rat hippocampal cells that ethanol and PMA utilize the same mechanism to act on stimulus-secretion coupling.…”
Section: Discussionmentioning
confidence: 56%