Enzymes noncompetitive

Table 3.4 Some examples of noncompetitive enzyme inhibitors in clinical use or trials...

H3. Hashida, S., Tanaka, K., Yamamoto, N., Uno, T, Yamaguchi, K., and Ishikawa, E., Detection of one attomole of [Arg ]-vasopressin by novel noncompetitive enzyme immunoassay (hetero-two-site complex transfer enzyme immunoassay). J. Biochem. (Tokyo) 110, 486-492 (1991). 

Yamaguchi K, Ishbcawa E. Detection of one attomole of [Arg8] -vasopressin by novel noncompetitive enzyme immunoassay. J Biochem 1991 110 486-92. 

S Hashida, et al. Novel and sensitive noncompetitive enzyme immunoassay (hetero-... 

Figure 7 12 Linewcaver-Burk plot for noncompetitive enzyme inhibition.

Lin, J., Yan, F., and Ju, H. (2004) Noncompetitive enzyme immunoassay for carcinoem bryonic antigen by flow injection chemiluminescence. Clinica Chimica Acta, 341, 109 115. 

Dimethirimol and ethirimol are effective fungicides at concentrations in the plant of approximately 10M. At the sublethal level concentration in the fungi is probably half that in the plant. Hence, it is assumed that these active substances act as noncompetitive enzyme inhibitors (Bent, 1970 Sampson, 1969 Calderbank,... 

Fig. 5.6. Graphic representation of competitive and noncompetitive enzyme inhibition.

FIGURE 6.9 A Lineweaver-Burk plot for the case of noncompetitive enzyme inhibition at three concentrations of the inhibitor. 

Identify the factors that affect enzyme activity. (Section 10.6) Compare the mechanisms of competitive and noncompetitive enzyme inhibition. (Section 10.7) Describe the three methods of cellular control over enzyme activity. (Section 10.8)... 

Distinguish between competitive and noncompetitive enzyme inhibition. 

Noncompetitive Enzyme-Linked Interaction Assay (ELIA)... 

An important feature of enzymes is that their active sites can often be occupied by, or react with, molecules other than the substrate, leading to inhibition of enzyme activity. Several inhibition mechanisms are known, but it is necessary only to distinguish between irreversible and reversible inhibition. Irreversible inhibition arises when the inhibitor molecule I dissociates very slowly or not at all from the enzyme active site. The best-known examples occur when I reacts covalently with a critical residue in the active site. Inhibition of cholinesterase enzymes by the reaction of organo-phosphorus compounds with a serine residue is a case in point. This type of inhibition is said to be noncompetitive—enzyme activity cannot be restored by addition of excess substrate. So although addition of I reduces V,n x, Km is unaffected. The double-reciprocal plot in such cases has the same. v-axis intercept as the plot for the uninhibited enzyme, but greater slope. 

Gelatin (2 mg/ml) and ribose (30 mM) were incubated in the presence of plant extracts (10 pg/ml) in 100 mM Sodium phosphate buffer at 37 C for 7 days, followed by the determination of CMA by a noncompetitive enzyme-linked immunosorbent assay (ELISA). 

Indicate whether each of the following describes a competitive or a noncompetitive enzyme inhibitor ... 

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