Title: Biocytin
CAS Registry Number: 576-19-2
CAS Name: N6-[5-(Hexahydro-2-oxo-1H-thieno[3,4-d]imidazol-4-yl)-1-oxopentyl]-L-lysine
Additional Names: e-N-biotinyl-L-lysine; biotin complex of yeast
Molecular Formula: C16H28N4O4S
Molecular Weight: 372.48
Percent Composition: C 51.59%, H 7.58%, N 15.04%, O 17.18%, S 8.61%
Literature References: A naturally occurring complex of biotin. Contains 65.6% biotin. Isoln: Wright et al., J. Am. Chem. Soc. 72, 1048 (1950); 74, 1996 (1952). Structure: Peck et al., ibid. 72, 1048 (1950); 74, 1999 (1952). Synthesis: Wolf et al., ibid. 74, 2002 (1952); Weijlard et al., ibid. 76, 2505 (1954); Wolf, Folkers, US 2710298 (1955 to Merck & Co.). Purification: McCormick, Föry, Methods Enzymol. 18 (pt A), 413 (1970). Review: A. F. Wagner, K. Folkers, Vitamins and Coenzymes (Wiley, New York, 1964) pp 138-159.
Properties: Crystals, mp 241-243°. Upon rapid crystn from dil methanol or dil acetone, mp 228-230° (dec); upon slow crystn sinters at 227°. mp 245-252° (dec, microblock). Crystals from water, mp 228.5°. [a]D25 +53° (c = 1.05 in 0.1N NaOH). Infrared absorption spectrum: J. Am. Chem. Soc. 74, 2001 (1952). Freely sol in water, glacial acetic acid. Less sol in alc. Practically insol in acetone and most other organic solvents. When subjected to strong acid hydrolysis (at least 3N at 120° for one hour) biocytin yields biotin and L-lysine. Forms a crystalline hydrochloride. Biocytin is characterized microbiologically by its availability as a source of biotin to Lactobacillus casei, L. delbrückii LD 5, L. acidophilus, Streptococcus fecalis R, Neurospora crassa, and Saccharomyces carlsbergensis and by its unavailability as a source of biotin to Lactobacillus arabinosus, L. pentosus, and Leuconostoc mesenteroides P-60.
Melting point: mp 241-243°; mp 228-230° (dec); mp 245-252° (dec, microblock); mp 228.5°
Optical Rotation: [a]D25 +53° (c = 1.05 in 0.1N NaOH)
Bioflavonoids Biopterin Bioresmethrin Biotin l-Sulfoxide Biperiden

Abbreviations Bct
CAS number 576-19-2 N
PubChem 7098660
ChemSpider 75634 YesY
ChEBI CHEBI:27870 YesY
Jmol-3D images Image 1
Molecular formula C16H28N4O4S
Molar mass 372.48 g mol−1
Melting point ~245 °C
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Biocytin is a chemical compound that is an amide formed from the vitamin biotin and the amino acid L-lysine. As an intermediate in the metabolism of biotin, biocytin occurs naturally in blood serum and urine.

The enzyme biotinidase cleaves biocytin and makes biotin available to be reused by other enzymes. Because biocytin is the natural substrate of the enzyme biotinidase, biocytin can be used to measure the biotinidase activity and therefore diagnose biotinidase deficiency.

Biocytin is also used in scientific research as a histological stain for nerve cells.[2]