Enzymes analogous

ENZYMATIC ANALYSIS WITH CARBOXYPEPTIDASES. Carboxypeptidases are enzymes that cleave amino acid residues from the C-termini of polypeptides in a successive fashion. Four carboxypeptidases are in general use A, B, C, and Y. Carboxypeptidase A (from bovine pancreas) works well in hydrolyzing the C-terminal peptide bond of all residues except proline, arginine, and lysine. The analogous enzyme from hog pancreas, carboxypeptidase B, is effective only when Arg or Lys are the C-terminal residues. Thus, a mixture of carboxypeptidases A and B liberates any C-terminal amino acid except proline. Carboxypeptidase C from citrus leaves and carboxypeptidase Y from yeast act on any C-terminal residue. Because the nature of the amino acid residue at the end often determines the rate at which it is cleaved and because these enzymes remove residues successively, care must be taken in interpreting results. Carboxypeptidase Y cleavage has been adapted to an automated protocol analogous to that used in Edman sequenators. 

Thus, AMDase requires no cofactors and this fact is entirely different from those of known analogous enzymes, such as acyl-CoA carboxylases, methylmalonyl-CoA decarboxylases " and transcarboxylases. 

Zaborina O, M Latus, J Eberspacher, LA Golovleva, F Lingens (1995) Purification and characterization of 6-chlorohydroquinol 1,2-dioxygenase from Streptomyces rochei 303 comparison with an analogous enzyme from Azotobacter sp. strain GPl. J Bacterial Yll 229-234. 

Obtaining starting values of parameters, as from information on analogous enzymes ... 

To investigate the cofactor requirement and the characteristics of the enzyme, the effects of additives were examined using phenylmalonic acid as the representative substrate. The addition of ATP or ADP to the enzyme reaction mixtures, with or without coenzyme A, did not enhance the rate of reaction. From these results, it is concluded that these co-factors are not necessary for this decarboxylase. It is well estabhshed that avidin is a potent inhibitor of the bio-tin-enzyme complex [11 -14]. In the present case, addition of avidin has no influence on the decarboxylase activity, indicating that the AMDase is not a biotin enzyme. Thus, the co-factor requirements of AMDase are entirely different from those of known analogous enzymes, such as acyl-CoA carboxylases [15], methyhnalonyl-CoA decarboxylases [11] and transcarboxylases [15,16]. 

Information is currently available which allows more definite conclusions than have previously been possible. Rate enhancements have been obtained in several simple chemical reactions that are of similar magnitude to those observed in analogous enzyme-catalysed reactions, and the goal of analysing the individual factors that can give such large rate accelerations is now perhaps within reach. The recent work will be stressed in this review. 

An exactly analogous enzymic transformation is encountered during the formation of oestrogen and androgen sex hormones, e.g. estradiol and testosterone respectively, where dehydroepiandrosterone is oxidized to androstenedione. 

Complementary structures of biological materials, especially those of proteins, often result in specific recognitions and various types of biological affinity. These include many pairs of substances, such as enzyme-inhibitor, enzyme-substrate (analog), enzyme-coenzyme, hormone-receptor, and antigen-antibody, as summarized in Table 11.2. Thus, bioaffinity represents a useful approach to separating specific biological materials. 

Serotonergic neurons. Analogous enzymes, transport pumps, and receptors exist in the 5HT neuron (Figs. 5 — 34 through 5—42). For synthesis of serotonin in serotonergic... 

Analogs enzymes catalyzing the same reaction but that are structurally unrelated. 

The antiviral specificity of acyclovir is due to the drug s higher affinity for viral DNA polymerase rather than the analogous enzyme in human cells42 Also, the first step in the phosphorylation of acyclovir is greatly accelerated in virus-infected cells versus healthy cells. Hence, the amount of the activated (phosphorylated) form of acyclovir is much greater in the cells that really need it—that is, cells infected with the virus. 

Chromosomal metallo-beta-lactamases that hydrolyze carbapenem antibiotics, such as imipenem, meropenem, or biapenem, are present in some Stenotro-phomonas, Bacteroides, andAeromonas strains [26], Some clinical/5, aeruginosa and Serratia marcescens isolates have a plasmid that carries metallo-beta-lactamase genes [26], These enzymes are not inactivated by inhibitors of serine-based beta-lactamases such as clavulanic acid or sulbactam analogs. Enzyme-... 

Yes. Chloramphenicol inhibits the peptidyltransferase of the 50S ribosomal subunit of bacteria, while cycloheximide inhibits the analogous enzyme in the 60S subunit of eukaryotic ribosomes. Their structures are shown below. 

All methylene-H4MPT dehydrogenases (both types) purified so far are monofunctional. In the H4folate system, the analogous enzyme can be monofunctional, or may have methenyl-H4folate cyclohydrolase and/or formyl-H4folate synthetase activity [362-371]. 

Hepatic glycogenosis (type VI) (G.H. Hers, 1959) is due to hepatic phosphorylase deficiency. Subtype Via is caused by a lack of phos-phorylase-B kinase, and it is transmitted by the x-chromosomal recessive route. Subtype Vib shows a deficiency in glycogen phosphorylase, and its transmission is autosomal recessive. In the musculature, the analogous enzyme is, however, intact. Nevertheless, there is pronounced genetic and phenotypical heterogeneity. 

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