Emlen L. Cresson

Affinity of avidin for biocytin.

Summary Avidin has a greater affinity for biotin than for biocytin. The affinity ratio for biocytin, as previously defined, is about 4.

Affinity of avidin for certain analogs of biotin.

Summary The avidin combinability of a number of compounds having some structural similarity to biotin was investigated. The specificity of the avidin reaction was emphasized by the finding that of the 19 compounds studied avidin possessed significant affinity only for δ- (2,3-ureylene-cyclohexyl-) valeric acid (XVII), γ- (3,4-ureylene-cyclohexyl)-butyric acid (XVIII) and δ-(3,4-ureylene-cyclohexyl )-valeric acid (XIX). The relative affinity ratio for Compound XVII was found to be about 14. Compounds XVIII and XIX, although definitely capable of combining with avidin, had affinity ratios too high for practical measurement.

Biocytin in Bacterial Deamination of Aspartic Acid

Summary Biocytin, like biotin, has been shown to be active in stimulating the aspartic acid deaminase system of bacterial cells that have been inactivated by exposure to pH 4 M phosphate buffer.

Biotin in the bacterial deamination of certain amino acids.

Summary Inactivation of bacterial aspartic acid deaminase activity by exposure of cells to pH 4 M phosphate buffer and its reactivation with biotin has been confirmed.