在这周出版的《生物化学杂志》（JBC）中，有一篇文章报道红辣椒粉不仅能给人带来热辣的感觉，其中的活性化合物能直接诱导发热，在该过程中细胞将能量直接转化为热量。
辣椒素（Capsaicin，CPS）是红辣椒粉中含有的一种化合物，它能带来辛辣的感觉；CPS能刺激一种在嗅感觉神经中发现的受体，然后引起热辣的感觉并带来发红和出汗的反应。
最近，Yasser Mahmoud发现辣椒素通过改变一种名为SERCA的肌蛋白的活性，以更直接的方式产“热”。一般情况下，肌肉收缩会伴随一个钙离子释放高峰，钙离子从肌浆网（sarcoplasmic reticulum, SR）区域释放出来，然后SERCA再将钙离子泵回SR（利用ATP能量），使肌肉松弛，循环发生该过程。
但是，CPS能与SERCA结合并使其“泵”的活性“解耦合”，这样就使蛋白质继续燃烧ATP能量，但却不是用于泵回钙离子。因此，所有的ATP能量都作为热量而散发。这种解耦合就是生热反应，它是维持体温的一种重要方式，常见于冬眠动物。Mahmoud指出，辣椒素是第一种已知的能够增强产热过程的天然化合物。
这些发现进一步解释了摄入辣椒素后能提高代谢速度和体温的原因。尽管这些研究需要的辣椒素数量非常之大（可能多于任何人能食用的量），但可以利用辣椒素的结构作为模型，设计可用于临床上治疗低温症的潜在化合物。（生物谷Bioon.com）
生物谷推荐原始出处：
JBC，doi：10.1074/jbc.M803654200，Yasser Ahmed Mahmmoud
Capsaicin stimulates uncoupled ATP hydrolysis by sarcoplasmic reticulum calcium pump
Yasser Ahmed Mahmmoud
Institute of Physiology and Biophysics, University of Aarhus, Aarhus C DK-8000
Corresponding Author: yam@biophys.au.dk
In muscle cells, the sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA) couples the free energy of ATP hydrolysis to pump Ca2+ ions from the cytoplasm to the SR lumen. In addition, SERCA plays a key role in non-shivering thermogenesis through uncoupled reactions, where ATP hydrolysis takes place without active Ca2+ translocation. Capsaicin (CPS) is a naturally occurring vanilloid, the consumption of which is linked with increased metabolic rate and core body temperature. Here, we document the stimulation by CPS of the Ca2+-dependent ATP hydrolysis by SERCA without effects on Ca2+ accumulation. The stimulation by CPS was significantly dependent on the presence of a Ca2+ gradient across the SR membrane. ATP activation assays showed that the drug reduced the nucleotide affinity at the catalytic site whereas the affinity at the regulatory site increased. Several biochemical analyses indicated that CPS stabilizes an ADP-insensitive E2P related conformation that dephosphorylates at a higher rate than the control enzyme. Under conditions where uncoupled SERCA was specifically inhibited by the treatment with fluoride, low temperatures, or dimethyl sulfoxide, CPS had no stimulatory effect on ATP hydrolysis by SERCA. It is concluded that CPS stabilizes a SERCA sub-conformation where Ca2+ is released from the phosphorylated intermediate to the cytoplasm instead of the SR lumen, increasing ATP hydrolysis not coupled with Ca2+ transport. To the best of our knowledge, CPS is the first natural drug that augments uncoupled SERCA, presumably resulting in thermogenesis. The role of CPS as a SERCA modulator is discussed. Bioon.com
