{{chembox | ImageFile=lathosterin.svg | ImageSize=210px | ImageFile1 = Lathosterol molecule ball.png | ImageSize1 = 260 | ImageAlt1 = Ball-and-stick model of lathosterol | IUPACName=5α-Cholest-7-en-3β-ol | SystematicName=(1''R'',3a''R'',5a''S'',7''S'',9a''S'',9b''R'',11a''R'')-9a,11a-Dimethyl-1-[(2''R'')-6-methylheptan-2-yl]-2,3,3a,5,5a,6,7,8,9,9a,9b,10,11,11a-tetradecahydro-1''H''-cyclopenta[''a'']phenanthren-7-ol | OtherNames= |Section1={{Chembox Identifiers | ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}} | ChemSpiderID = 59151 | InChI = 1/C27H46O/c1-18(2)7-6-8-19(3)23-11-12-24-22-10-9-20-17-21(28)13-15-26(20,4)25(22)14-16-27(23,24)5/h10,18-21,23-25,28H,6-9,11-17H2,1-5H3/t19-,20+,21+,23-,24+,25+,26+,27-/m1/s1 | InChIKey = IZVFFXVYBHFIHY-SKCNUYALBG | StdInChI_Ref = {{stdinchicite|correct|chemspider}} | StdInChI = 1S/C27H46O/c1-18(2)7-6-8-19(3)23-11-12-24-22-10-9-20-17-21(28)13-15-26(20,4)25(22)14-16-27(23,24)5/h10,18-21,23-25,28H,6-9,11-17H2,1-5H3/t19-,20+,21+,23-,24+,25+,26+,27-/m1/s1 | StdInChIKey_Ref = {{stdinchicite|correct|chemspider}} | StdInChIKey = IZVFFXVYBHFIHY-SKCNUYALSA-N | CASNo_Ref = {{cascite|correct|??}} | CASNo=80-99-9 | PubChem=65728 | ChEBI_Ref = {{ebicite|correct|EBI}} | ChEBI = 17168 | SMILES = O[C@H]1CC[C@@]2([C@@H]3\C(=C/C[C@H]2C1)[C@@H]4CC[C@H]([C@H](C)CCCC(C)C)[C@]4(CC3)C)C }} |Section2={{Chembox Properties | Formula=C<sub>27</sub>H<sub>46</sub>O | MolarMass=386.65 g/mol | Appearance= | Density= | MeltingPt= | BoilingPt= | Solubility= }} |Section3={{Chembox Hazards | MainHazards= | FlashPt= | AutoignitionPt = }} }}

'''Lathosterol''' is a cholesterol-like molecule found small amounts in humans.<ref>{{cite journal |last1=Myant N.M. |date= 1981|title=The Distribution of Sterols and Related Steroids in Nature |url= |journal=The Biology of Cholesterol and Related Steroids |volume= |issue= |pages= 123–159|doi=10.1016/B978-0-433-22880-6.50010-2 |isbn= 9780433228806|access-date=}}</ref> The enzyme Δ7-sterol 5(6)-desaturase converts it to 7-dehydrocholesterol. It is accumulated in lathosterolosis.<ref>{{cite book |last1=Ho |first1=A. C. C. |last2=Fung |first2=C. W. |last3=Siu |first3=T. S. |last4=Ma |first4=O. C. K. |last5=Lam |first5=C. W. |last6=Tam |first6=S. |last7=Wong |first7=V. C. N. |title=JIMD Reports - Volume 12 |chapter=Lathosterolosis: A Disorder of Cholesterol Biosynthesis Resembling Smith-Lemli-Opitz Syndrome |date=2013 |volume=12 |pages=129–134 |doi=10.1007/8904_2013_255 |pmid=24142275 |pmc=3897790 |isbn=978-3-319-03460-7 }}</ref>

==Biosynthesis== The final step in the biosynthesis of lathosterol is by reduction of the double bond in the sidechain of the sterol 5α-cholesta-7,24-dien-3β-ol when acted on by the enzyme Δ<sup>24</sup>-sterol reductase, which uses nicotinamide adenine dinucleotide phosphate (NADPH) as its cofactor.<ref>{{KEGG enzyme|1.3.1.72}}</ref><ref>{{cite journal | vauthors = Bae SH, Paik YK | title = Cholesterol biosynthesis from lanosterol: development of a novel assay method and characterization of rat liver microsomal lanosterol delta 24-reductase | journal = Biochem. J. | volume = 326 | pages = 609&ndash;16 | pmid = 9291139 | pmc = 1218712 | year = 1997 | issue = 2 | doi = 10.1042/bj3260609 }}</ref>

{{chemrxn|width=60%| {{chemrxn/cpd|qid=Q27101835|caption=5α-cholesta-7,24-dien-3β-ol }} {{chemrxn/txt|+ NADPH }} {{chemrxn/arw|direction=reversible|fwd_in={{chem2|H+}}|rev_out={{chem2|H+}} }} {{chemrxn/cpd|lathosterol }} {{chemrxn/txt|+ NADP<sup>+</sup> }} }}

==In cholesterol biosynthesis== In vertebrates, lathosterol is an intermediate in the pathway to cholesterol via 7-dehydrocholesterol.<ref name=KEGG>{{KEGG enzyme|1.14.19.20}}</ref><ref>{{cite journal | vauthors = Dempsey ME, Seaton JD, Schroepfer GJ, Trockman RW | year = 1964 | title = The Intermediary Role of Δ<sup>5,7</sup>-cholestadien-3-β-ol in Cholesterol Biosynthesis | journal = J. Biol. Chem. | volume = 239 | pages = 1381&ndash;7 | doi = 10.1016/S0021-9258(18)91325-6 | doi-access = free | pmid = 14189869 }}</ref><ref>{{cite journal | vauthors = Nishino H, Nakaya J, Nishi S, Kurosawa T, Ishibashi T | year = 1997 | title = Temperature-induced differential kinetic properties between an initial burst and the following steady state in membrane-bound enzymes: studies on lathosterol 5-desaturase | journal = Arch. Biochem. Biophys. | volume = 339 | pages = 298&ndash;304 | pmid = 9056262 | doi = 10.1006/abbi.1996.9871 | issue = 2 }}</ref> The enzyme Δ7-sterol 5(6)-desaturase catalyses the oxidation reaction:

{{chemrxn|width=60%| {{chemrxn/cpd|lathosterol|upright=2 }} {{chemrxn/txt|+ {{chem2|2 Fe(2+)}} + 2 {{chem2|H+}} }} {{chemrxn/arw|direction=reversible|fwd_in={{chem2|O2}}|fwd_out={{chem2|2 H2O}}|rev_in={{chem2|2 H2O}}|rev_out={{chem2|O2}} }} {{chemrxn/sub|class=skin-invert-image|caption=7-dehydrocholesterol }} {{chemrxn/txt|+ {{chem2|2 Fe(3+)}} }} }}

It uses two molecules of the cofactor ferrocytochrome b<sub>5</sub> with two protons and one oxygen for each molecule of lathosterol converted.<ref name=KEGG/>

==See also== * Lathosterol oxidase

==References== {{Reflist}}

{{Steroids and intermediates}}

Category:Cholestanes Category:Sterols