Absorption spectra, hemoglobin

Examination of a small number of blood samples from patients with various diseases involving blood abnormalities have not shown any of these conditions to be associated with a fetal-type hemoglobin absorption spectrum with the exception of Cooley s anemia, a congenital disease which is common in certain Mediterranean countries. Liquori (1951) has found that blood from cases of this type of anemia has a slow alkali denaturation rate, comparable with that observed for fetal-type hemoglobin by Jonxis (1949), which enables it to be clearly distinguished from the normal adult type, which is denatured much more rapidly under the same conditions. 

Hb possesses both 4 and 5-coordinate forms as demonstrated by the Raman spectra (Figure 1) and the spj it Soret band of the absorption spectrum (9,36). In contrast, Mb shows only the red Soret component and the Raman lines characteristic of the 5-coordinate form. Thus, myoglobin s R-like structure favors the 5-coordinate form. The R/T difference in affinity for histidine might also be expected to reveal itself in the strength of the Ni-histidine bond. In native Fe hemoglobin, the Fe-histidine bond increases in strength upon conversion from the T to R structure (31,39). 

Figure 34.9 shows an absorption spectrum from the abdomen of the mouse. There was intense absorption of hemoglobin in the visible region, and the onset of absorption of water in the near-1R region (>900 nm). The integral sphere was found to be useful in order to obtain the absorption spectra of the abdomen of a mouse. 

The light absorption spectrum of the hemoglobin derivative to be chosen for a photometric determination should have a number of favorable properties. It should display a rather flat maximum. If this is not the case, slight alterations in filter or in photometer characteristics will introduce considerable errors. Furthermore, the light absorption maximum should... 

The light absorption spectrum of SHb shows an absorption maximum at X = 618-622 nm (Fig. 18), which can be used for determination purposes. The addition of CN does not affect this peak, while the Hi maximum at X = 630 nm disappears completely through the formation of HiCN (Section 7.1). Use of this property serves to distinguish between these two hemoglobin derivatives. 

The main problems in determining BSP in biological fluids are background absorbance due to other pigments, such as bilirubin or hemoglobin, or to lipemic turbidity, and the effect of protein-binding on the absorption spectrum. 

Hemoglobin E shows a striking change in electrophoretic mobihty with change in pH. At pH 6.5 its mobility is greater than that of A and slightly less than that of S, and at pH 8.8 it is nearly identical with that of C. The absorption spectrum, solubility, and lability to alkali denaturation of E are similar to those of A. i... 

Spectroscopic methods aim to detect the UV-visible absorption spectrum of hemoglobin or one of its derivatives. 

D. Oxyhemoglobin plus 0.02% nitrite and 0.1% ascorbic acid. Typical absorption spectrum of nitric oxide hemoglobin. Bright red. 

The absorption spectrum of oxyhemoglobin is markedly different from that of hemoglobin. The former has two sharp well-defined absorption bands between D and E, while the latter has only one. Such differences in the absorption spectra cannot be explained on the grounds of a difference in state, nor in the degree of dispersion of the hemoglobin. Rather it indicates a change in the chemical composition of the two substances. 

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