lactate - is it really an acid?
lactate is a "strong anion" under physiologic conditions, that is to say, its pK being 3.87,
it is almost completely dissociated in the pH range of 6 to 8.
even at a pH of 7 its undissociated counterpart, lactic acid,
is only present at a concentration of 0.00074 mEq/l, when the lactate concentration is 1mmol/l.
you can calculate its ionisation (and the negative ionisation of albumin, phosphate and trometamol) for different pH values
by following this link!.
furthermore lactate and NOT lactic acid is the product of glycolysis! lactate's carboxyl goup originates in the reaction of
1,3-biphosphoglycerate to 3-phosphoglycerate + phosphate; this carboxyl group is from its very beginning an anion devoid of
a hydrogen atom. anaerobic glycolysis leads to lactate formation - this has been and remains true -, and it also leads to acidosis.
the H+-ions, though stem from ATP hydrolysis, and the formation of lactate from pyruvate actually reduces acidosis!
source and much recommended reading:
source: Robergs et alii, Biochemistry of Exercise-induced Metabolic Acidosis,
Am J Physiol Regulatory Integrative Comp Physiolog 2004; 287:502-516
still, it is true that the formation of lactate reduces the strong ion difference, thereby shifting the acid-base balance to
more acidic values. strictly speaking, though, no lactic acid has been implicated in this!
