INDEX dipeptide

Many bixxer compounds contain both hydrophobic and hydrophilic sites which can alter cell membranes through penetration. There is a correlation between bitter intensity and hydrophobicity-solubility indexes such as fee octanol/water partition coefficient, lo (7). Penetration may directly affect cAMP phosphodiesterase as part of fee transduction process (see below). A bitter receptor protein may be involved wife certain bitters, such as specific structural requirements wife fee bitter tasting dipeptides and denatonium salts (27). The latter is used in some consumer products to avoid accidental ingestion. A receptor mechanism is also supported by fee existence of a genetic "taste blindness" for some bitter materials (see below). 

The same types of A-acyl-O-alkyl derivatives can also be used for GC analysis of the simplest oligopeptides (at least dipeptides and tripeptides). Other, obsolete, recommendations on the GC analysis of these compounds include various sequences for their reduction by LiAlH4 into polyaminoalcohols, followed by N-acylation or per-methylation and, finally, silylation of OH groups. For example, A-TFA dipeptide Phe-Phe after reduction and silylation gives the compound (III) with a retention index of 2390 on semistandard-phase Dexsil-300. 

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