Sulfhydryl groups functional

As seen in Figure 1, the organo sulfur compounds are methylated at the boiling point (90°C) of dimethyl carbonate, whereas methylation (or alkylation with other alkyl groups) of other functional groups requites higher temperatures. This has resulted in the selective methylation of sulfhydryl groups of compounds that contain other substituents that can be alkylated. The other substituents can then be alkylated at elevated temperatures (63). 

This intermediate attacks compounds containing a variety of functional groups, such as primary, secondary, and tertiary amino nitrogen atoms, carboxyl groups, and sulfhydryl groups (10). 

Heavy metals with no known biological function, such as aluminum, arsenic, lead, and mercury, are nonessential metals.4-5 These metals are toxic because they can irreversibly bind to enzymes that require metal cofactors. Toxic metals readily bind to sulfhydryl groups of proteins.6-7 In fact,... 

Protein functional groups able to react with anhydrides include the oc-amines at the N-terminals, the s-amine of lysine side chains, cysteine sulfhydryl groups, the phenolate ion of tyrosine residues, and the imidazolyl ring of histidines. However, acylation of cysteine, tyrosine, and histidine side chains forms unstable complexes that are easily reversible to regenerate the original group. Only amine functionalities of proteins are stable to acylation with anhydride reagents (Fraenkel-Conrat, 1959 Smyth, 1967). 

Although the primary utility of active halogen compounds is to modify sulfhydryl groups in proteins or other molecules, the reaction is not totally specific. Iodoacetyl (and bromoacetyl) derivatives can react with a number of functional groups within proteins the sulfhydryl group of cysteine, both imidazolyl side chain nitrogens of histidine, the thioether of methionine, and... 

Reactive double bonds are capable of undergoing addition reactions with sulfhydryl groups. A popular example of this type of functional group is the maleimide group (Section 2.2, this... 

The first two compounds discussed in this section are truly sulfhydryl-reactive, using the common iodoacetyl and maleimide functionalities, respectively. The third derivative, however, is not reactive directly with sulfhydryl groups, but contains a protected sulfhydryl which, after deprotection, can be used to react with other sulfhydryl-reactive crosslinkers. 

Colman, R.F. (1969) The role of sulfhydryl groups in the catalytic function of isocitrate dehydrogenase. I. Reaction with 5,5 -dithiobis(2-nitrobenzoic acid). Biochemistry 8, 888. 

Lead (soft, Pb2+) Injuries to peripheral nervous system, disturbs heme synthesis and affects kidneys Pb2+ may replace Ca2+ with loss of functional and structural integrity. Reacts with sulfhydryl groups, replaces Zn2+ in 8-aminolevulinic acid dehydratase. 

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