Electrochemical sensors for the determination of hydrogen sulfide production in biological samples - Electrochemical Sensors, Biosensors and Their Biomedical Applications - page 226

8.6.1.3 Intact tissues and organs
Intact rat aorta, combined fresh weight average of 24 mg, in the respirometer chamber at
approximately 5 M O 2 exhibited H 2 S production when supplied with PLP and L-cysteine

or homocysteine (Fig. 8.8). Aorta H 2 S production typically exhibited a pronounced pla-
teau that could be sustained for

µ

30 min, suggesting the establishment of a dynamic
steady state between H 2 S production and consumption at approximately 1 to 2 µ M H 2 S.

The addition of 1 M Lucina pectinata metHb I to the respirometer chamber caused the

PHSS signal to abruptly drop, again indicating signal specifi city to H 2 S (Fig. 8.8).

µ

8.6.2 Measurement of H 2 S consumption
8.6.2.1 Isolated mussel gill mitochondria
H 2 S consumption was exhibited by mitochondria isolated from the gills of the marine
ribbed mussel Geukensia demissa , an inhabitant of sulfi de-rich intertidal sediment, in an

6 M Sulfide

8 min

10 mM BCA

2 mM L-cys
1 mM PLP

1 mM BCA

4 M Sulfide

1 mM BCA

2 min

1 mM L-cys
1 mM PLP

cells cells

3 M Sulfide

20 min
300 uM L-cys
10 uM PLP

2 mM BCA

3 uM metHb

FIGURE 8.8 H 2 S production in vascular tissues. H 2 S production by aorta homogenate (upper panel), cul-
tured rat vascular smooth muscle cells (VSMCs; middle panel), and intact rat aorta occurs after the addition
of substrate L-cysteine (L-cys) and cofactor pyridoxal L-phosphate (PLP) for the enzyme CGL located in vas-
cular tissue. H 2 S production is inhibited after the CGL. β cyano-L-alanine (BCA) is added. Ferric Lucina pec-
tinata hemoglobin I (metHb) is added to confi rm H 2 S production. The quantity of metHb-sulfi de produced,
determined spectrophotometrically, matched the levels of H 2 S detected by the PHSS (after [41]).