Blue Horse

Figure 10.2 A purple mule, not a blue horse and a red donkey.

Fig. 8. Model for the high affinity complex between horse Cc and CcO determined by Roberts and Pique (34). The backbone of horse Cc and CcO subunit II are shown with the side chains of selected lysines and acidic residues colored blue and red, respectively. The residue numbers on subunit II are for R. sphaeroides CcO. Van der Waals surfaces are shown for Cc heme and subunit II Trp143 and Met263. The CuA coppers are represented by green Corey-Pauling-Koltun models. Reprinted with permission from Ref. (18). Copyright 1999, American Society of Biochemistry and Molecular Biology.

Effect of substrate concentration. In the following experiments the cholinesterase activities were measured by a continuous titration method. The digest of acetylcholine and horse-serum cholinesterase (total vol. 10 ml.), containing bromothymol blue and 0-0002 m phosphate, was titrated with 0-01 n NaOH to maintain the pH at 7-4. The titrations, which were carried out at 20°, were linear over a period of 10-15 min. The velocity was expressed as ml. 0-01 n NaOH/5 min. under the conditions used, it was proportional to the enzyme concentration. When an inhibitor was added, this was equilibrated with the enzyme, etc., for 5 min. at 20° before adding the substrate contained in a volume of 1 ml. 

Optical brightening was discovered in 1929 by P. Krais [22], The whiteness of viscose rayon and semibleached flax yam was increased by treatment with an aqueous solution of esculin (1) [531-75-9] and drying. Krais recognized that this effect was due to the strong blue fluorescence of esculin, a 3-D-glucoside of 6,7-dihy-droxycoumarin that is obtained by extracting horse chestnut bark. (For historical references, see [23].)... 

Figure 1. (a) X-ray crystal structure of horse-heart ferricytochrome c.8 All protein atoms are shown in the C.-P.-K. form, while the heme group is shown in the stick form. All Arg and Lys residues are colored blue, while Glu and Asp are colored in red, to contrast the destribution of the most ionizable side chains, (b) The X-ray crystal structure of horse heart ferricytochrome c in complex with horse cytochrome c peroxidase (cep).9 The peroxidase is shown as a molecular surface model, with blue regions depicting positive and red representing negative electrostatic potential. Note the cluster of negative potential on ccp that surrounds the contact interface. 

Fig. 6.3. SDS/PAGE (5-15% linear gradient gel) separated proteins of the total worm homogenate and isolated brush border fractions from protoscoleces of Echinococcus granulosus (horse strain), (a) Coomassie blue staining (b) Periodic acid-Schiff (PAS) staining. (After McManus Barrett, 1985.)...

Meanwhile, I branded the memory of him onto my inner eye. Again and again I opened the door and discovered him on the porch, his forehead dewy with sweat and his eyes a light blue. He was so broad-shouldered that I couldn t see past him, though his stamping horse had been somewhere in the background. 

Figure 3 X-ray crystal structure of horse heart c)hochrome c. Lysine residues surrounding the heme crevice are blue, and the heme is red...

As we stress in the following section, Fe + does not simply exit from the core of ferritin. Watt et al. (144) have completely reduced the core of horse ferritin and shown that it has a pH-dependent redox potential corresponding to 2H+ taken up by the core for each Fe + reduced to Fe ". In this study, anaerobic gel-filtration columns were used to separate reduced and partially reduced ferritin from contaminating small ions, and Mossbauer spectroscopy was employed to determine the extent of core reduction. Very little of the core iron was lost during the preparation, consistent with the low yields of Prussian blue formed by the addition of [FefCNle] to reduced ferritin (73, 146). Partially reduced ferritin cores have Mossbauer spectra indicative (50) of an iron... 

The Trypan dyes are bisazo compounds distantly related to the sulfonamides. Trypan blue, a bluish-gray, water-soluble powder, was one of the first drugs to be used for the treatment of piroplasmo-sis and trypanosomiasis. Trypan blue is effective against B. caballi but not B. equi. In horses, a freshly prepared 1-2% solution of Trypan blue can be administered by slow i.v. injection at 2-3 mg/kg for premunition. Rapid i.v. administration of Trypan blue may result in shock. Subcutaneous administration of Trypan blue should be avoided because it causes skin sloughing. Trypan blue stains the mucous membranes and other tissues blue and is, therefore, not used commonly. 

Eserine blue (250), formed from a reaction of rubreserine with ammonia (315), was reported to exhibit very low potency in a horse serum butyrylcholinesterase assay (314). A later communication (316)suggests total inactivity of these latter two physostigmine derivatives. 

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