Sickle cell mutant

Restriction analysis can be used to detect sickle cell disease prenatally, since the DNA of all cells, including amniotic cells, carries the mutant DNA. It is much more difficult to obtain fetal blood for the analysis of the mutant hemoglobin A P-chain. Furthermore, fetal blood is composed mostly of fetal hemoglobin, sinee-hemoglobin A is made later in development. 

It has been proposed that a major source of oxygen radicals in sickle erythrocytes is mutant hemoglobin HbS. However, although HbS showed an accelerated autoxidation rate under in vitro conditions, its in vivo oxidative activity was not determined. Sheng et al. [401] suggested that the observed oxidation rate of HbS is exaggerated by adventitious iron. Dias-Da-Motta et al. [402] proposed that another source of enhanced superoxide production in sickle cells are monocytes in contrast, there is no difference in superoxide release by sickle... 

Deoxygenated sickle cell hemoglobin (deoxyHbS), the j8-Glu-6-Val point mutant form of adult hemoglobin, appears to obey the following empirical rate law for nucleation of polymerization ... 

Sickle cell anemia is caused by synthesis of a mutant form of hemoglobin, hemoglobin 5 or HbS), in which a glutamic acid at position 6 of the hemoglobin (3 subunit is replaced by valine. 

The answer is B. Sickle cell anemia is caused by inheriting two copies of a mutant P glo-bin gene that leads to synthesis of sickle hemoglobin, HbS. A severe case of sickle cell anemia would most likely have demonstrated symptoms and been diagnosed before the age of 6. However, he may only be a carrier, with one copy each of normal P-globin and one of the sickle allele, a condition called sickle cell trait. Nevertheless, the patient s... 

The genetic change that produced the mutant hemoglobin in sickle cell anemia can be classified as which type of mutation ... 

There are many abnormal or mutant hemoglobins, some of which cause pathological conditions. One is sickle-cell hemoglobin (HbS), in which the glutamate residue in the sixth position of the normal human hemoglobin (HbA) /3 chain has been replaced by valine. This position, referred to as /36, is on the outside of the hemoglobin molecule. Individuals who... 

Sickle cell anemia Human P-globin mutant 11, 12... 

DNA probes are now used routinely to detect the presence of mutant alleles in fetal cells obtained by amniocentesis, as well as in cells removed from affected adults or carriers. Many inherited disorders, such as sickle cell disease, cystic fibrosis, Huntington s disease, Duchenne s muscular dystrophy, and dozens of other Mendelian (single-gene) disorders, can now be diagnosed in fetuses and adults. In addition to inherited disorders, DNA probes are used to detect the presence of active oncogenes or inactive tumor suppressor genes in cancerous tissues removed from patients (Chapter 26). 

Q.26.3 The difference between normal hemoglobin A and the sickle-cell hemoglobin mutant protein is a single amino acid replacement of glutamate with valine in the fi chains. (Each hemoglobin molecule is composed of 2a and 2fi chains). The mobility of these two proteins can be measured as +0.3 X 10 m2/s - V and —0.2 x W m /s - V. 

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