| active succinate | The condensation product of succinic acid and CoA; one of the intermediates of the tricarboxylic acid cycle and a precursor in the synthesis of haem. Synonym: active succinate, succinyl-CoA. (05 Mar 2000) |
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| active sulfate | 3'-phosphoadenosine 5'-phosphosulfate;an intermediate in the formation of urinary ethereal sulfates, notable for containing a "high energy" sulfate bond; the 3'-OH of adenosine is replaced by -OPO3H2, the 5'-OH by -OP(O2H)-OSO3H. Synonym: active sulfate. Acronym: PAPS (05 Mar 2000) |
| active transport | <biochemistry, chemistry> Transport of ions, nutrients or other molecules into a cell against a concentration gradient, this requires the expenditure of energy through ATP hydrolysis. (06 May 1997) |
| active treatment | A therapeutic substance or course intended to ameliorate the basic disease problem, as opposed to supportive or palliative treatment. Compare: causal treatment. (05 Mar 2000) |
| active vasoconstriction | Reduced caliber of a vessel caused by increased tonus in the smooth muscle in its walls. (05 Mar 2000) |
| active vasodilation | Vasodilation caused by decrease in tonus of smooth muscle in the wall of a vessel. (05 Mar 2000) |