Renalase does not catalyze the oxidation of catecholamines

Article abstract of DOI:10.1016/j.abb.2015.05.016

Abstract It is widely accepted that the function of human renalase is to oxidize catecholamines in blood. However, this belief is based on experiments that did not account for slow, facile catecholamine autoxidation reactions. Recent evidence has shown that renalase has substrates with which it reacts rapidly. The reaction catalyzed defines renalase as an oxidase, one that harvests two electrons from either 2-dihydroNAD(P) or 6-dihydroNAD(P) to form β-NAD(P)⁺ and hydrogen peroxide. The apparent metabolic purpose of such a reaction is to avoid inhibition of primary dehydrogenase enzymes by these β-NAD(P)H isomers. This article demonstrates that renalase does not catalyze the oxidation of neurotransmitter catecholamines. Using high-performance liquid chromatography we show that there is no evidence of consumption of epinephrine by renalase. Using time-dependent spectrophotometry we show that the renalase FAD cofactor spectrum is unresponsive to added catecholamines, that adrenochromes are not observed to accumulate in the presence of renalase and that the kinetics of single turnover reactions with 6-dihydroNAD are unaltered by the addition of catecholamines. Lastly we show using an oxygen electrode assay that plasma renalase activity is below the level of detection and only when exogenous renalase and 6-dihydroNAD are added can dioxygen be observed to be consumed.

Full text of DOI:10.1016/j.abb.2015.05.016

Archives of Biochemistry and Biophysics 579 (2015) 62–66
Contents lists available at ScienceDirect
Archives of Biochemistry and Biophysics
journal homepage: www.elsevier.com/locate/yabbi
Renalase does not catalyze the oxidation of catecholamines
,1
⇑
Brett A. Beaupre, Matthew R. Hoag, Graham R. Moran
Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 N. Cramer St, Milwaukee, WI 53211-3209, United States
a r t i c l e i n f o
a b s t r a c t
Article history:
Received 6 April 2015
and in revised form 28 May 2015
Available online 3 June 2015
It is widely accepted that the function of human renalase is to oxidize catecholamines in blood. However,
this belief is based on experiments that did not account for slow, facile catecholamine autoxidation reac-
tions. Recent evidence has shown that renalase has substrates with which it reacts rapidly. The reaction
catalyzed defines renalase as an oxidase, one that harvests two electrons from either 2-dihydroNAD(P) or
6-dihydroNAD(P) to form b-NAD(P)+ and hydrogen peroxide. The apparent metabolic purpose of such a
reaction is to avoid inhibition of primary dehydrogenase enzymes by these b-NAD(P)H isomers. This arti-
cle demonstrates that renalase does not catalyze the oxidation of neurotransmitter catecholamines. Using
high-performance liquid chromatography we show that there is no evidence of consumption of epinephr-
ine by renalase. Using time-dependent spectrophotometry we show that the renalase FAD cofactor spec-
trum is unresponsive to added catecholamines, that adrenochromes are not observed to accumulate in
the presence of renalase and that the kinetics of single turnover reactions with 6-dihydroNAD are unal-
tered by the addition of catecholamines. Lastly we show using an oxygen electrode assay that plasma
renalase activity is below the level of detection and only when exogenous renalase and 6-dihydroNAD
are added can dioxygen be observed to be consumed.
Keywords:
Renalase
FAD
Oxidase
Catecholamines
NAD
Dioxygen
Ó 2015 Elsevier Inc. All rights reserved.
Introduction
in a quiescent state that can only be activated in blood in the
presence of specific catecholamine neurotransmitters [5,8].
Renalase is widely defined to be a kidney-derived flavoprotein
enzyme/hormone whose function is to oxidize circulating cate-
cholamines in order to lower blood pressure and slow the rate of
contraction of the heart [1–7]. The initial basis of this claim for
renalase activity was an exceedingly small accumulation of hydro-
gen peroxide in the presence of common neurotransmitter cate-
cholamines when assayed using a generic Amplex Red-based
oxidase assay. However, in these initial experiments no account,
in the form of a control reaction, was made for background autox-
idation [1,5,7–9]. Catecholamines are prone to oxidation in the
presence of dioxygen due to their capacity to form semiquinones
[10]. The superoxide ion that results rapidly disproportionates to
The chemical transformation ultimately claimed for renalase was
that oxidized and cyclized aminochrome molecules were the
native products and that the reaction was somewhat faster in the
presence of NAD(P)H [8]. However, even in these latter studies,
no control was made for the addition of the catecholamine or the
reductant, despite that NAD(P)H would greatly increase the com-
plexity of the assay by increasing the number of non-enzymatic
redox reactions that yield H2O2 (Scheme 1). That no control
reactions were used to support any of the early catalytic claims
emphasizes the overall tenuous foundation on which renalase
catecholamine oxidase activity is based.
Boomsma and Tipton were first to register well-reasoned
skepticism concerning a catecholamine oxidase role for renalase
[11] and were joined by others expressing similar dissent and
eventually direct experimental refutation was presented by
Pandini et al. [12–14]. However, the flawed initial in vitro evidence
and counter evidence have been insufficient to quell the passive
consensus that the function of renalase is to oxidatively consume
catecholamine neurotransmitters from blood. Consequently, the
early claims for catecholamine oxidase activity continue to be
adduced and correlated with a wide variety of physiological
measurements [2–7,9,15–40].
dioxygen and hydrogen peroxide providing
a
steady
non-enzymatic background signal for an Amplex Red assay
(Scheme 1). The very low level of H2O2 production was
subsequently rationalized by proposing that renalase is isolated
⇑
Corresponding author. Fax: +1 (414) 229 5530.
E-mail address: moran@uwm.edu (G.R. Moran).
This research was supported by a National Science Foundation Grant to G.R.M.
1
(CHE-1402475) and by
Initiative Grant to G.R.M.
a University of Wisconsin-Milwaukee Research Growth
http://dx.doi.org/10.1016/j.abb.2015.05.016
0003-9861/Ó 2015 Elsevier Inc. All rights reserved.

B.A. Beaupre et al. / Archives of Biochemistry and Biophysics 579 (2015) 62–66
63
Scheme 1. Non-enzymatic redox reactions in renalase catecholamine oxidase assays.
We recently demonstrated that 2-dihydroNAD (2DHNAD(P))
and 6-dihydroNAD(P) (6DHNAD(P)), both isomers of b-NAD(P)H
(4DHNAD(P)), rapidly reduce the FAD2 coenzyme of renalase
(230 sÀ1 for 6DHNAD, 850 sÀ1 for 2DHNAD) and in doing so become
oxidized to b-NAD(P)+. The reduced enzyme then reoxidizes by
renalase [1,2,4,5,23], is consumed by renalase, a mixture of
b-NADH (50 M) and epinephrine (150 M) was prepared in PBS
buffer at 25 °C. The sample was then divided into two and renalase
(9 M final) was added to one while the other served the role of a
sample age control. A second set of mixtures were prepared in an
identical manner, but FAD (9 M final) was added in place of rena-
l
l
l
reducing molecular oxygen to form H2O2 (2.9 Â 103 MÀ1 sÀ1
)
l
(Scheme 2). Moreover, this genuinely catalytic reaction has an
apparent metabolic purpose, as both 2DHNAD and 6DHNAD are inhi-
bitory to primary metabolism dehydrogenases [41,42]. The funda-
mental purpose of this study is corrective; using a verifiably active
form of renalase, we demonstrate that no catalytic link exits
between renalase and catecholamine oxidation. We show also that
renalase is not activated by blood plasma nor is, what we surmise
to be, the native activity influenced by the presence catecholamines.
lase. All samples were incubated for 10 min prior to ultrafiltration
using a 0.5 mL Amicon 10 kDa centrifugal filter (removing renalase
from the mixture). 50
matographed by HPLC using a Xterra C18 reversed phase column
(4.6 Â 150 mm, 3.5 M particle size) run isocratically at 0.4 ml/min
lL of each filtrate was then chro-
l
in 10 mM potassium phosphate pH 7.5 coupled to a 600 E HPLC
pump and Waters 2487 dual wavelength detector (260 nm and
340 nm). Components eluting from the HPLC column were identi-
fied by their characteristic retention time compared to authentic
compounds. The chromatograms derived from the renalase and
FAD samples were corrected for the minor dilution that occurred
with the addition of these components.
Materials and methods
Materials
Potassium phosphate, L-DOPA, epinephrine hydrochloride, and
Spectrophotometric evidence of neurotransmitter oxidation
sodium chloride were obtained from ACROS. Dopamine hydrochlo-
ride was purchased from Alfa Aesar. Renalase was expressed and
purified according to our previously published methods [43]. b
NADH (disodium salt, trihydrate) was obtained from Amresco;
b-NAD+ was purchased from Sigma. 6DHNAD was prepared by
reduction of b-NAD+ as previously described [41]. Human blood
plasma was a gift from Dr. Julie A. Oliver (Biological Sciences
Department-University of Wisconsin-Milwaukee). Freshly drawn
blood was treated with 10 U/mL heparin (Sagent Pharmaceuticals)
to inhibit clotting. The sample was centrifuged at 2200 rpm until
blood cell pellet was formed (ꢀ15 min). The plasma was separated
from the blood cell pellet and hematocrit and stored on ice until
needed. Plasma samples were collected, purified, diluted (50%
PBS), and used in experiments within 3 h.
Reactions were performed to assess the rates of autoxidation of
catecholamines in the presence of renalase (or FAD control) when
incubated with a reductant (b-NADH or 6DHNAD). Renalase was
prepared by dilution to 40
a onto a Hitech-DX2 (now TgK) stopped-flow spectrophotometer
l
M in 2Â PBS buffer and mounted onto
instrument. Reaction mixtures in which renalase (or FAD control)
was combined with 100
lM catecholamine (epinephrine, dopa-
mine or -DOPA) and 15
L
lM b-NADH (or 6DHNAD control) in water
were observed at 458 nm which allows observation of both the
FAD redox state and the formation of aminochrome species (kmax
ꢀ 480 nm). All solutions were equilibrated with atmosphere at
25 °C and contained ꢀ250
lM dioxygen.
To assess if catecholamine neurotransmitters (epinephrine,
HPLC product analysis
dopamine and -DOPA) modulate the catalytic behavior of rena-
L
lase, single turnover reactions with 6DHNAD were performed in
the presence and absence of catecholamines with atmospheric
In order to demonstrate the extent to which epinephrine, the
catecholamine most often claimed or accepted as a substrate for
dioxygen (ꢀ250
subsequent reoxidation of the renalase flavin coenzyme can be
clearly observed. A native substrate solution, 6DHNAD (30 M),
lM). Under these conditions the reduction and
2
l
Abbreviations used: HPLC, high performance liquid chromatography; L-DOPA,
L-3,4-dihydroxyphenylalanine; Dopamine, 4-(2-aminoethyl)benzene-1,2-diol; Epi-
nephrine, (R)-4-(1-hydroxy-2-(methylamino)ethyl)benzene-1,2-diol; FAD, flavin ade-
nine dinucleotide; b-NAD+, oxidized nicotinamide adenine dinucleotide; b-NADH
(4DHNAD), reduced nicotinamide adenine dinucleotide; 6DHNAD,
6-dihydronicotinamide adenine dinucleotide; 2DHNAD, 2-dihydronicotinamide ade-
nine dinucleotide ; renalase, human renalase variant 1.
was prepared in H2O. This solution was mounted onto the
stopped-flow spectrophotometer and mixed with the renalase
(40 lM) sample described above and the turnover was observed
at 458 nm, the visible absorption maximum for the FAD coenzyme
bound to the enzyme. To determine if catecholamine

64
B.A. Beaupre et al. / Archives of Biochemistry and Biophysics 579 (2015) 62–66
Scheme 2. Proposed native catalytic chemistry of renalase.
neurotransmitters modulate the turnover of renalase, 200
lM of
epinephrine, dopamine or
tion before mixing.
L-DOPA was added to the 6DHNAD solu-
Dioxygen consumption to assess renalase activity in blood and the
effect of preincubation
In order to establish the constitutive level of renalase activity in
human blood and the effect of preincubation with plasma and/or
epinephrine as compared to PBS buffer control, a variety of assays
were monitored by dioxygen consumption. Reactions were
observed using a Hansatech Oxygraph oxygen electrode and all
reaction components were pre-equilibrated with atmospheric
Fig. 1. HPLC analysis of oxidation of epinephrine to adrenochrome by renalase. (A)
and (B) were separated using a Xterra reverse phased C18 run isocratically in
10 mM Kpi, pH 7.5 and monitored at 260 nm. (A) The blue line represents the
dioxygen (ꢀ250
ing final concentrations: 50% human blood plasma (diluted in PBS
buffer), 10 M epinephrine, 500 nM renalase and 30 M 6DHNAD.
lM) at 25 °C. Reactants were added to the follow-
mixture of 150
25 °C before the addition of 9
addition of 9 M renalase and incubation for 10 min at 25 °C; renalase was removed
lM epinephrine and 50
lM b-NADH (4DHNAD) in PBS buffer at
lM renalase and the red trace was taken after the
l
l
l
Each assay was initiated by the addition of 6DHNAD, following
either a 5 min or 20 min preincubation and then observed for an
additional 700 s.
from the sample by centrifugal (Amicon) ultra-filtration prior to injection. (B) The
reaction described in A was repeated except FAD was substituted for renalase. (For
interpretation of the references to color in this figure legend, the reader is referred
to the web version of this article.)
Results
Spectrophotometric evidence of neurotransmitter oxidation
HPLC product analysis
Renalase has been reported to oxidize catecholamines to
aminochromes (Scheme 1) [9]. It has also been proposed that cat-
echolamines modulate the redox activity of renalase to the extent
that the enzyme is largely inactive in the absence of epinephrine
[8]. In order to show the capacity of renalase to oxidize cate-
cholamines to form aminochromes, two sets of reactions were per-
formed one in the presence and one in the absence of renalase.
Aminochromes are the oxidized and cyclized forms of catecholami-
nes that have a puce color as a result of a broad absorption cen-
tered around 480 nm (e480 ꢀ 4020 MÀ1 cmÀ1) which provides a
simple physical signal to observe their accumulation in solution.
The absorption peak of aminochromes is sufficiently broad that
at 458 nm, the wavelength of observation used, the extinction
coefficient is only 2% lower, permitting simultaneously assessment
of the FAD coenzyme and the catecholamine oxidation/cyclization.
Three common neuroactive catecholamines were mixed with
Renalase is claimed to consume neuroactive catecholamines,
chiefly epinephrine, in order to lower blood pressure [8]. To
demonstrate the extent to which verified active renalase can con-
sume epinephrine in the presence of b-NADH, standardized HPLC
chromatograms were collected and compared to controls that con-
tained FAD in place of renalase (Fig. 1). 150
lM Epinephrine was
combined with 50
l
M b-NADH (that has a b-NAD+ impurity). The
sample was divided into two and renalase added to one. Both sam-
ples were then incubated for 10 min (Fig. 1A). Two similar mix-
tures were prepared as controls but with FAD substituted for
renalase (Fig. 1B). Analysis of the chromatograms showed that no
significant consumption of epinephrine could be observed in the
10-min window of the incubation. The renalase sample did show
significant loss of b-NADH (11
l
M) that was not entirely accounted
for by a gain in the b-NAD+ peak area (2
lM). This fraction of the
reductant (b-NADH or 6DHNAD) and renalase (20
FAD (20 M final). In the first control b-NADH was combined with
epinephrine, -DOPA, or dopamine and subsequently mixed with
renalase to determine if renalase could enhance the rate of oxida-
tion of the catechols to their associated aminochromes in the pres-
ence of NADH. No change in absorbance was observed indicating
that renalase does not promote the oxidation and cyclization cate-
cholamines. As a control, FAD was substituted for renalase and the
above experiment repeated. This data showed small accumulations
lM final) or
b-NADH was accounted for by the modest dissociation constant
for RenÅox b-NADH complex (Kd ꢀ 600
l
M) and the ꢀ20-fold
M) during filtration
lM retention [41]. The FAD control
l
L
increase in the renalase concentration (180
that together predict the 11
l
chromatograms indicate no non-enzymatic chemistry has occurred
within the 10 min incubation window. Together these data defini-
tively show that the consumption of epinephrine cannot be
detected in the presence of high concentrations (9
active renalase.
lM) of fully

B.A. Beaupre et al. / Archives of Biochemistry and Biophysics 579 (2015) 62–66
65
of absorption (epinephrine, 0.0035; DOPA, 0.015;
L-DOPA, 0.0025)
equating to ꢀ1–3 M aminochrome after 300 s, indicating that a
l
mixture of b-NADH and free FAD can enhance the rate of cate-
cholamine autoxidation and that renalase actually provides some
degree of protection from this chemistry presumably as a result
of the active site flavin being inherently unreactive with
b-NAD(P)H molecules in order to avoid wasteful diaphorase
activity.
In our previous work we have demonstrated that renalase cat-
alyzes rapid oxidation of 6DHNAD(P) and 2DHNAD(P) to
b
NAD(P)+ where a hydride equivalent is transferred from the nicoti-
namide base to the renalase flavin coenzyme that then reoxidizes
by reducing dioxygen to form hydrogen peroxide (Scheme 2)
[41,43,44]. In order to show the extent of the influence of cate-
cholamines on the kinetics of this chemistry, reduction and reox-
idaton of the renalase flavin coenzyme that occurs in single
turnover with 6DHNAD was observed at 458 nm (Fig. 2B). The data
obtained indicate that neither epinephrine, L-DOPA, or dopamine
have influence on the catalytic behavior of renalase. The FAD,
6DHNAD ( catecholamines) control for the single turnover reac-
tions where ostensibly the same as those for FAD, b-NADH and cat-
echolamine in Fig. 1A (data not shown).
Fig. 3. The effect of catecholamine and plasma preincubation. Renalase activity in
50% blood plasma and PBS buffer was determined by monitoring dioxygen
consumption. Reactions were performed by reacting 30
lM 6DHNAD in the
absence or presence of 500 nM renalase and 10 M epinephrine in either PBS
l
buffer or 50% blood plasma. Traces 1, 2, 6, and 7 (from top) were incubated at 25 °C
for 20 min prior to the addition of 6DHNAD all other traces were incubated at 25 °C
for 5 min before 6DHNAD addition. Traces were aligned so the addition of 6DHNAD
appears in the same time position in all reactions. Assays were separated by adding
or substracting values for clarity. Only Assay 5 is not plotted on an actual molecular
oxygen scale.
Dioxygen consumption to assess renalase activity in blood and the
effect of preincubation
There are three near constant elements in all scientific articles
that pertain to renalase; all claims for activity involve the reduc-
tion of dissolved dioxygen, most report or cite that catecholamines
are substrates and the majority pivot their investigations on the
role of renalase in blood [14,45]. Moreover, the low in vitro cate-
cholamine oxidase activity has been claimed to be a consequence
of a ‘‘prorenalase’’ form that is largely inactive when separated
from some unidentified activator [5,9]. Given that renalase oxi-
dizes 2- and 6DHNAD(P) [41], does renalase exhibit modified cat-
alytic behavior in blood? In order to demonstrate the effects of
preincubation with catecholamine and/or blood plasma we con-
ducted a series of assays using an oxygen electrode (Fig. 3). All
assays had 6DHNAD added either after a short (5 min) or long
(20 min) preincubation.
that the basal level of renalase activity in blood is sufficiently low
to be below the sensitivity of these methods. Using antibody detec-
tion, Zbroch et al. determined that the concentration of renalase in
plasma was 4 lg/mL (100 nM) [31] approximately one fifth of the
exogenous concentration added in assays 2, 3, 4, 7, 8 & 9. That each
of these traces show marked dioxygen consumption with added
renalase and those without show no dioxygen consumption
(assays 1 & 5) suggests that there is very little renalase in blood
or that the majority of it is inactive. Comparison of assays 2 & 4
to assays 7 & 9 indicates that preincubation of renalase in plasma
does not alter its behavior. Both sets of assays indicate linear con-
sumption of dioxygen that is equimolar to the amount of 6DHNAD
added and then cessation of activity. Assays 2, 3 & 4 show recovery
of approximately half the dioxygen consumed in the renalase cat-
alytic phase presumably as a consequence of catalase activity in
the plasma. Contrary to claims that epinephrine activates renalase
[8], neither assay 1 or 6, those preincubated with epinephrine in
plasma and PBS respectively, show any evidence of activity,
strongly suggesting that the circulating catecholamine does not
activate a quiescent form of renalase.
In Fig. 3, assays 1 & 6, we see that epinephrine is slow to oxidize
and does not promote significant consumption of dioxygen prior to
or after the addition of 6DHNAD. In addition, assays 1 & 5 indicate
Discussion
The chronology of reported activities for renalase elaborate the
erroneous initial claim. In the progenitor article it was proposed
that renalase is secreted by the kidney to oxidize circulating cate-
cholamines and that the electrons mobilized are delivered to
dioxygen [1]. However, this was surmised only from the data
obtained from a generic oxidase assay method and without the
use of appropriate controls. Nonetheless, the association of rena-
lase with catecholamines continues to become ever more con-
flated. Catecholamines are said to regulate the activity, secretion
and synthesis of renalase [5]. A variety of complex regulatory feed-
back pathways have been proposed [5–7,17,23]. Aminochromes
are claimed as the native products [9] and the active oxidizing
agent is said to be superoxide [8]. However, the extremely low
levels of claimed in vitro catecholamine oxidase activity has been
Fig. 2. Catalytic turnover of renalase in the presence of neurotransmitters. (A and B)
Renalase single turnover (B) and control(A) stopped-flow spectrophotometer traces
were observed at 458 nm for 200 sec. (A) The extent of auto-oxidation of
epinephrine was monitored; top, stopped-flow spectrophotometer trace of 20
renalase with 15 M b-NADH (4DHNAD) in the absence and presence of 100
catecholamine of interest (epinephrine, DOPA,
spectrophotometer trace of 20 M FAD with 15 M b-NADH(4DHNAD) and 100
of catecholamine of interest (epinephrine, DOPA,
20 M renalase with 15 M 6DHNAD in the absence and presence of 100
catecholamine of interest (epinephrine, DOPA, -DOPA).
l
l
M
M
l
L
-DOPA); bottom; stopped-flow
l
l
lM
L
-DOPA). (B) Single turnover of
l
l
lM
L

66
B.A. Beaupre et al. / Archives of Biochemistry and Biophysics 579 (2015) 62–66
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cited as a deficit by a number of researchers [11,14,46] and this
was then rationalized by invoking ‘‘prorenalase’’ a claimed quies-
cent form of the enzyme that requires activation [5,6] that occurs
only in blood in the presence of a catecholamine [5,8]. It can
now be stated with some certainty that this successive affirmative
set of claims describes a compounding of an initial scientific defi-
cit; the failure to employ appropriate control reactions to assess
catalysis.
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The purpose of this study is to clearly demonstrate that renalase
is not the third monoamine oxidase. The apparently indelible mark
of the early and recent activity claims for renalase must be dis-
pelled if the field is to advance in a purposeful manner. We
recently reported two isomeric forms of b-NAD(P)H as substrates
for renalase that are clearly catalytically consumed (Fig. 2B) and
have redefined renalase as having a house-keeping activity that
is unrelated to blood pressure regulation. Renalase functions
instead to oxidize reduced forms of nicotinamide adenine dinu-
cleotides that harbor the hydride in non-metabolically accessible
positions of the nicotinamide base (positions 2 & 6). We have pro-
posed that this activity exists to relieve inhibition of primary meta-
bolism by these molecules. A principal benefit of having identified
native substrates for renalase is that we can now test the validity of
previously proposed activities using a form of the enzyme that we
have verified is fully active (Fig. 2B) [41]. In sum our data show that
renalase does not consume catecholamines (Figs. 1 and 2A), is not
kinetically regulated by catecholamines (Fig. 2B), is not isolated in
an inhibited form and as such cannot be activated by blood plasma
or catecholamines (Fig. 3). In addition, our data suggests that blood
has very little if any active renalase (Fig. 3) an observation that is
consistent with its newly identified activity that we would suggest
has an exclusively intracellular/metabolic role.
Catecholamines form hydrogen peroxide as they oxidize in oxy-
genated media. That the initial accounts of renalase activity did not
employ appropriate control reactions and reported vanishingly low
activity undermines the subsequent affirmative claims. The case
has also been made that in the absence of genuine substrates, no
sample integrity measures have been established and as such there
has been no means to discriminate natively folded and active rena-
lase from misfolded inactive but soluble renalase [14]. The vast
majority of reports that describe direct use of the enzyme do not
indicate the color of the protein (that is conspicuously yellow) or
the unique absorption maxima of the flavin in the natively folded
enzyme [47]. Nonetheless, in the ten years since its initial discov-
ery, the terms renalase and monoamine oxidase C have become
somewhat synonymous [17,48,49] and this has occurred despite
sound argument and evidence to the contrary [11,12,14]. In this
article we have presented evidence that verifiably active renalase
does not catalyze the oxidization of catecholamines.
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Conflict of interest
There is no conflict of interest.
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