THE PHOSPHATASES OF HUMAN ERYTHROCYTES

The Phosphatases of Human Erythrocytes

By HELEN QUINCY WOODARD, PH.D. V ARIOUS investigatorst5 have reported that erythrocytes exhibit phosphatase activity at pH values between 4 and 6, and some believe that this is due to two acid phosphatases with maximum activities at about pH 4.2. and .6. Reports on alkaline phosphatase activity have been less numerous.’ ‘ 6 , 7 In the course of an investigation of the glycerophosphatase activit...

Kinetic comparison of genetically different acid phosphatases of human erythrocytes.

Properties of the acid phosphatases of erythrocytes and of the human prostate gland.

There is much evidence indicating the non-identity of acid phosphatases of different origin. Davies (1934) has shown that the acid phosphatase of the red cell differs from that of spleen in that the former hydrolyses x-glycerophosphate much more readily than the ,-compound, while with the spleen enzyme ,-glycerophosphate is hydrolysed more quickly. Kutscher & Worner (1936) described the irrever...

THE ISOLATION OF ENZYME TRANSKETOLASE FROM HUMAN ERYTHROCYTES: THE CHARACTERIZATION OF ITS QUARTERNARY STRUCTURE

Human erythrocyte transketolase (sedoheptulose-7-phosphate: D-glyceraldehyde-3-phosphate, glycolaldehyde transferase, E.C. 2.2.1.1.) has been isolated from erythrocytes with a specific activity of 59.84 U/mg. SDS-PAGE and SE-HPLC were used both as a measure of purity and as a preparative mean to obtain a higher degree of purity. Four protein bands corresponding to molecular weights of 32,0...

Serine/threonine protein phosphatases and regulation of K-Cl cotransport in human erythrocytes.

Activation of K-Cl cotransport is associated with activation of membrane-bound serine/threonine protein phosphatases (S/T-PPases). We characterize red blood cell S/T-PPases and K-Cl cotransport activity regarding protein phosphatase inhibitors and response to changes in ionic strength and cell size. Protein phosphatase type 1 (PP1) activity is highly sensitive to calyculin A (CalA) but not to o...