Saccharomyces cerevisiae enzyme activity

Co-for-Zn substitution in alcohol dehydrogenase from Saccharomyces cerevisiae revealed a 100-fold increase in activity and a higher resistance of the modified protein to the inhibitory action of other divalent transition metals,1208 making the Co-modified enzyme suitable for biotechnological applications. 

Histone kinases responsible for N-phosphorylation have been isolated from regenerating rat liver [109] and Walker-256 carcinosarcoma cells [110]. One kinase with a pH optimum of 9.5 phosphorylated His-18 and His-75 of H4, while the other with a pH optimum of 6.5 phosphorylated lysine of HI. The enzyme from regenerating rat liver phosphorylated H4 at 1-phosphoryl histidine, while the carcinosarcoma enzyme phosphorylated H4 His at the position 3 [111]. Both kinases were cAMP independent [110]. Matthews and colleagues purified a 32-kDa histidine H4 kinase from yeast, Saccharomyces cerevisiae [112,113]. The enzyme phosphorylated His-75 (1-phosphoryl histidine) in H4. His-18 of H4 and other histidines in other core histones were not phosphorylated by this kinase [112]. Protein phosphatases 1, 2A, and 2C could dephosphorylate His-75 of H4 [114]. Applying a gel kinase approach to detect mammalian H4 histidine kinases, Besant and Attwood detected four activities in the 34-41 kDa range with extracts from porcine thymus [115]. 

Human Set9 is a 50 kDa H3 methyltransferase that methylates Lys-4 of H3. The enzyme methylated free H3 but not H3 in chromatin substrates. There is evidence that Set9 may stimulate activated transcription [198]. Set9 has the SET domain but lacks the cysteine-rich (pre-SET and post-SET) domains. Disruption of Saccharomyces cerevisiae and Saccharomyces pombe Setl obliterates H3 methyl Lys-4 [199]. Thus this SET domain containing protein appears to be a H3 Lys-4 methyltransferase, catalyzing both di- and tri-methylation of H3 Lys-4 [155]. However, studies with recombinant Setl failed to show histone methyltransferase activity. It has been suggested that other associated proteins may be required for the Setl to be catalytically active [139,200]. Indeed, Setl is associated with several... 

G. Legler and W. Lotz, Mechanism of action of glycoside-splitting enzymes. VII. Functional groups at the active site of an a-glucosidase from Saccharomyces cerevisiae, Hoppe-Seyler s Z. Physiol. Chem., 354 (1973) 243-254. 

This behaviour is in agreement with data obtained by Grizon [49], who observed a dependence of the ADH activity of whole dehydrated cells of Saccharomyces cerevisiae upon pH of the buffer. For practical application it seems also important to suspend cells at the optimal pH for the isolated enzyme. 

Using gel filtration on columns of Sephadex G-200, Gascon and Ot-tolenghi142 discovered in Saccharomyces cerevisiae a form of /3-D-fruc-tofuranosidase of low molecular weight, and predicted correctly that this form would be found to be free from carbohydrate. This enzyme occurred within the protoplast its molecular weight (135,000) and specific activity were similar to those of the protein moiety of the external enzyme. The two /3-D-fructofuranosidases gave the same Km for sucrose, the same Km for raffinose, and the same pH optimum (3.5 to 5.5) for enzymic activity but their pH-stability curves differed, the internal enzyme being reversibly inactivated under acidic conditions, that is, below pH 5. 

Substrate Specificity of Enzymes of Saccharomyces cerevisiae Having a-D-Glucosidase Activity"... 

The third subgroup of alcohol dehydrogenases consists of iron-activated enzymes. The first enzyme detected to belong to this group was the ADH II from Zymomonas mobilis [116] followed by the observation that the ADH IV from Saccharomyces cerevisiae shows more than 50% identity to this bacterial ADH [117]. No data about the secondary or tertiary structures of the enzymes in this subgroup are available currently. A prediction based upon the Chou and Fasman analysis [118] indicates that these enzymes are rich in a-helices. 

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