Yeast split

Several nucleoside hydrolases have been described. A hydrolase purified from baker s yeast (79) has been found which specifically degrades uridine to uracil and n-ribose. Another nucleoside hydrolase also purified from yeast splits guanoane, adenosine, inosine, xanthosine, nicotinamide riboside, and a group of synthetic unnatural riborides. A highly specific uridine hydrolase is found in yeast, and a nucleoride hydrolase has been described in Lactobacillus pentosus which degrades both purine and pyrimidine nucleosides (74)- A nonspecific hydrolase as well as a i cific inosine hydrolase have been purified from fish muscle (76). The spores of BaciUus eereus contain a heat-stable hydrolase which can cleave adenosine and inosine (76, 77). Finally, a riboside hydrolase of broad spedfidty which attacks only 9-ribofuranosides has been purified from extracts of Ladobacil-lus delbrueckii (72, 78). 

Cytochromes from bacterial, yeast, and mammalian sources have been investigated by Mossbauer spectroscopy (114—117). Horseheart cytochrome c and the c-type cytochrome from T. utilis show spectra characteristic of low-spin Fe(III) in the oxidized form of the protein and low-spin Fe(II) for the reduced form of the protein. Lang et al. (115) have analyzed the Mossbauer data in terms of a low-spin Hamiltonian in some detail. Cooke and Debrunner (116) present quadrupole data on dehydrated forms of oxidized and reduced cytochrome c the quadrupole splittings for hydrated and dehydrated forms of the reduced protein are quite similar in contrast to a difference of the oxidized form. No spin-state change is reported for either form of cytochrome c. 

Cytochrome P-450 enzymes have been isolated from a variety of mammalian tissues, insects, plants, yeasts and bacteria. The P-450 cytochromes (Gunter and Turner, 1991) are membrane bound mono-oxygenase enzymes which catalyse oxygen atom transfer to entrapped non-polar substrates. The binding of carbon monoxide to the enzyme produces a split in the 420 nm Soret band to give bands at 364 and 450 nm. The absorption at 450 nm distinguishes the hemoprotein from all others and hence provides... 

C. Neuherg and H. Fischer (1938). Enzymic splitting of triphosphoric acid. II. Hydrolysis by means of an enzyme found in Aspergillus niger and yeast. Analytical reactions of triphosphate. 

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