Methyl- 3-thiogalactoside

Figure 4. Design of synthesis routes to methyl 3- and 4-thiogalactosides. ...

Based on the K values for methyl-/3,D-galacto-pyranoside and methyl-/3,D-thiogalactoside, which compound is the more potent inhibitor of /3-galactosidase ... 

The starting methyl thiogalactoside 3, formed when D-galactose 2 was treated with methanethiol, was converted to 6-iodo sugar 4 via selective... 

When the phenyl thiogalactoside derivative 74 was treated with methyl pyruvate and boron trifluoride etherate without solvent, the mixed 3,4-acetals were obtained in 70% combined yield. When the reaction was repeated in the presence of dichloromethane, however, the only product obtained (30% yield) was the 1,6-anhydro-D-iodo compound 75. As illustrated in Scheme 7 it... 

Here, then, we have examples of the regulation of metabolism by a promotion or suppression of enzyme synthesis. What is not yet fully understood is how inducers promote and repressors inhibit the synthesis of new enzyme protein. When two inducer molecules are supplied simultaneously and when the rate of protein synthesis is limited by nitrogen supply then it is possible to demonstrate competition between the systems synthesising the adaptive enzymes in so far as one enzyme is synthesised the amount of the second enzyme formed is correspondingly reduced. Secondly, induction of an enzyme can sometimes be effected by a compound (chemically similar to the substrate) but not acted upon by the enzyme whereas other molecules which can act as substrates for the enzyme may be ineffective as inducers. Thus methyl-/S-o-thiogalactoside is a powerful inducer... 

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