Gilchrist J S, Katz S, Belcastro A N
Faculty of Graduate Studies, University of British Columbia, Vancouver, Canada.
Biochem Biophys Res Commun. 1990 Apr 16;168(1):364-71. doi: 10.1016/0006-291x(90)91717-7.
The effect of ATP upon difference absorbance due to Ca2+ and Mg2+ complexation with the metallochromic dye, Antipyrylazo III (AP III), was investigated. At divalent cation concentrations appropriate for Sarcoplasmic Reticulum Ca2+ transport, wavelengths (greater than 670 nm) were found whereupon the addition of up to 1mM nucleotide did not alter divalent cation:AP III difference absorbance. At these sample wavelengths an initial rapid uptake of Ca2+ by Heavy SR (HSR) was clearly resolved by dual wavelength spectroscopy of Ca2+:dye difference absorbance. Elimination of ATP interference of Ca2+:AP III absorbance by Mg2+ elevation (3-10mM) was shown to be an inappropriate general strategy for AP III spectroscopic studies of HSR Ca2+ transport due to Mg2+ inhibition of ryanodine receptor mediated Ca2+ release.
研究了ATP对因Ca2+和Mg2+与金属显色染料安替比拉佐III（AP III）络合而产生的吸光度差异的影响。在适合肌浆网Ca2+转运的二价阳离子浓度下，发现波长（大于670 nm），此时加入高达1 mM的核苷酸不会改变二价阳离子：AP III吸光度差异。在这些样品波长下，通过Ca2+：染料吸光度差异的双波长光谱法清楚地分辨出重肌浆网（HSR）对Ca2+的初始快速摄取。由于Mg2+抑制了兰尼碱受体介导的Ca2+释放，因此提高Mg2+（3 - 10 mM）消除ATP对Ca2+：AP III吸光度的干扰被证明是用于HSR Ca2+转运的AP III光谱研究的不合适的通用策略。
