The introduction of the C-22–C-23 ethylenic linkage in ergosterol biosynthesis

Akhtar, Muhammad; Parvez, Masood; Hunt, P. F.

doi:10.1042/bj1060623

Cited by 19 publications

(4 citation statements)

References 8 publications

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“…Professor D. H. R. Barton (personal communication) has noted a similar phenomenon with a related compound. The conversion of compound (XVI) into ergosterol is in agreement with the previous conclusion (Akhtar et al 1968) that the enzymes participating in the formation of the C-22-C-23 double bond in ergosterol biosynthesis do not require the activation of the C-24-C-28 double bond.…”

Section: Resultssupporting

confidence: 92%

Studies on the Biosynthesis of the ergosterol side chain

Akhtar

Parvez

Hunt

1969

Biochemical Journal

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1. A convenient synthesis of 24-methylene[23,25-(3)H(3)]dihydrolanosterol is described. 2. A general anaerobic-aerobic method for the incorporation of sterols into whole yeast cells is also described and illustrated by experiments with (3)H-labelled lanosterol. 3. The method was used to convert labelled 24-methylene-dihydrolanosterol into ergosterol, in good yield, by Saccharomyces cerevisiae. 4. Degradation of the biosynthetic ergosterol provided confirmation of the conversion, which supports the proposed mechanism for the biosynthesis of the ergosterol side chain. 5. Mechanisms for the further conversion of the 24-methylene side chain into the ergosterol side chain are discussed and it was shown that a compound, [3alpha-(3)H(1)]-ergost-7-en-3beta-ol, with a fully saturated side chain, can also be efficiently incorporated into ergosterol. 6. This result was confirmed by a procedure involving formation of the 5,8-epidioxide and subsequently the 5,8-epidioxy-22,23-epoxide of the biosynthetic ergosterol.

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Section: Resultssupporting

confidence: 92%

Studies on the Biosynthesis of the ergosterol side chain

Akhtar

Parvez

Hunt

1969

Biochemical Journal

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“…3H/14C ratio 18.5) was incubated with whole cells of Saccharomyce8 cereviiae by the method of Akhtar, Parvez & Hunt (1968). The isolated ergosterol (III) was converted into its epidioxide derivative (V), which had a 3H/14C ratio of 4.3 and hence 78.4% of the tritium radioactivity originally present in the lanosterol had been lost.…”

Section: (I) (Iii)mentioning

confidence: 99%

The stereochemistry of hydrogen elimination from C-7 in cholesterol and ergosterol biosynthesis

Akhtar

Rahimtula

Wilton

1970

Biochemical Journal

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The synthesis of [7alpha-(3)H]lanosterol is described. It is shown that in the conversion of [7alpha-(3)H,26,27-(14)C(2)]lanosterol into cholesterol by a rat liver system, it is the 7beta-hydrogen atom that is predominantly removed. On the other hand, the conversion of doubly labelled lanosterol into ergosterol by whole yeast cells results in the loss of the 7alpha-hydrogen atom. These results therefore suggest that the C-7 hydrogen atoms with opposite stereochemistry are labilized by the rat liver and the yeast Delta(8)-Delta(7) steroid isomerases.

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“…The corresponding 3-,-hydroxy (16-3H-labelled) compounds were prepared by exchange with methanolic 5% (w/v) KOH containing tritiated water (50mc/ ml.) (Akhtar, Parvez & Hunt, 1968). (c) Extraction and purification of steroids in the incubation mixture.…”

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confidence: 99%