P-8880 4α-Phorbol 12-Myristate 13-Acetate, >99%

Storage: Store at or below -20 ºC. Solubility: Soluble in DMSO or ethanol.

AK-106

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• Negative control for studies with PMA (Cat. No. P-1680). Van Duuren, B.L. et al., "Effects of structural changes on the tumor-promoting activity of phorbol myristate acetate on mouse skin." Cancer Res. 39: 2644-2646 (1979).
• Please request Technical Note #13 for additional information.
• 4α-Phorbol Ester Activation of TRPV4 Channels. Though long thought to be a biologically inactive or extremely weak phorbol ester analog (i. e., an ED₅₀ > 25 µM for binding to protein kinase C), 4α-PMA may prove to be a reasonably potent activator of TRPV4 channels, with utility for structure-activity studies of this phenomenon. The supposition of agonist activity for 4α-PMA on TRPV4 channels is based on the potent agonist response elicited by the very similar compound, 4α-PDD, in systems containing human VRL-2 and murine TRP12 channels. Watanabe, H. et al., "Activation of TRPV4 Channels (hVRL-2/mTRP12) by Phorbol Derivatives." J. Biol. Chem. 277: 13569-13577 (2002). See the entry for 4α-PDD (Cat. No. P-2170) for an extensive description of these new and exciting results.
• Chemical Structures. The primary structural difference between 4α-PMA and the highly potent phorbol ester-type PKC activators is the configuration at C4. In the highly active phorbol ester family, the hydroxy group at C4 is in the β configuration, rising up out of the two-dimensional structure as depicted on paper or a computer monitor. The 4-α-phorbol esters such as 4α-PMA, 4α-PDD and 4α-PDBu have the 4-OH group oriented down below the paper or computer screen's two-dimensional plane.
• Nomenclature. Unless "4α" is specified, all "phorbol" compounds are automatically defined, by operation of standard chemical nomenclature conventions, as having the 4β-configuration, as part of the intrinsic meaning of the word "phorbol". This is much like the word "cholesterol", which automatically means that its hydroxy group at carbon 3 is in the β configuration; there is no need to specify "3β-cholesterol", whereas a cholesterol derivative with a 3α hydroxy group would require a "3α-cholesterol" specification. To avoid confusion in this field, it is useful to note that, technically, 4α-PMA is not a "phorbol ester"; it is a "4α-phorbol ester", and the structural differences, though minor overall, are quite significant biologically. Given the extreme differences in their biological properties, both on PKC and TRPV4 channel-based phenomena, efforts to maintain distinctive names for members of these two biologically quite distinct classes of compounds appear to be well justified.
• Sold for laboratory or manufacturing purposes only; not for human, medical, veterinary, food, or household use.