364
PETER BERNFELD
remainder of the starch paste behaves toward the enzyme like soluble
starch, i.e., like a mixture of amylopectin and amylose, and is further
hydrolyzed accordingly.
4. Distribution of a-Amylase
This enzyme has been found abundantly throughout both the animal
and the vegetable kingdoms.
a. Animal a-Amylases. In vertebrates α-amylase occurs in a great
number of different tissues, organs, and fluids, but most of all in saliva
and pancreas. Many times lower concentrations of amylase have been
reported in the secretions of the small intestine, in liver, testes, thyroid,
the ruminant stomach, and adrenals, and also in blood, urine, milk,
TABLE II
COMPARATIVE AMYLASE ACTIVITIES OF TISSUES, ORGANS, AND FLUIDS
0
Source of
amylase
Serum
Lungs
Spleen
Heart
Kidney
Brain
Duodenum
Perirenal fat
Colon
Muscle
Liver
Pancreas
Saliva
pH7.0
Phosphate
2,010
663
543
464
652
52
66,400
644
3,960
202
781
2,810,000
626,000
c
Amylase activities
per 100 mg. tissue
Rats
pH7.6
Veronal
1,980
641
562
439
638
56
65,700
628
3,880
134
737
2,474,000
—
Ratio
0.99
0.97
1.03
0.94
0.98
1.08
0.99
0.98
0.98
0.66
0.94
0.88
—
in Somogyi units
or 100 ml. fluid
6
pH7.0
Phosphate
3,750
1,690
1,240
735
890
95
12,240
—
1,340
1,040
1,660
2,099,000
■ —
Mice
1
pH7.6
Veronal
3,360
1,590
1,210
710
840
91
12,500
—
1,310
900
1,620
,514,000
—
Ratio
0.90
0.94
0.98
0.97
0.94
0.96
1.02
—
0.98
0.87
0.98
0.72
—
° According to McGeachin et al. (44)·
b Determined according to the method of Van Loon et al. (46).
c Average of determinations in 15 individual animals, ranging from 91,000 to 1,340,000
units (45).
cerebrospinal fluid, and in the chicken egg (43). Many of the older
amylase determinations have been carried out in phosphate buffer, and
may include, therefore, phosphorylase activity. Newer measurements
(44) in Veronal buffer are more specific for amylase and yield results
shown in Table II.
PETER BERNFELD
remainder of the starch paste behaves toward the enzyme like soluble
starch, i.e., like a mixture of amylopectin and amylose, and is further
hydrolyzed accordingly.
4. Distribution of a-Amylase
This enzyme has been found abundantly throughout both the animal
and the vegetable kingdoms.
a. Animal a-Amylases. In vertebrates α-amylase occurs in a great
number of different tissues, organs, and fluids, but most of all in saliva
and pancreas. Many times lower concentrations of amylase have been
reported in the secretions of the small intestine, in liver, testes, thyroid,
the ruminant stomach, and adrenals, and also in blood, urine, milk,
TABLE II
COMPARATIVE AMYLASE ACTIVITIES OF TISSUES, ORGANS, AND FLUIDS
0
Source of
amylase
Serum
Lungs
Spleen
Heart
Kidney
Brain
Duodenum
Perirenal fat
Colon
Muscle
Liver
Pancreas
Saliva
pH7.0
Phosphate
2,010
663
543
464
652
52
66,400
644
3,960
202
781
2,810,000
626,000
c
Amylase activities
per 100 mg. tissue
Rats
pH7.6
Veronal
1,980
641
562
439
638
56
65,700
628
3,880
134
737
2,474,000
—
Ratio
0.99
0.97
1.03
0.94
0.98
1.08
0.99
0.98
0.98
0.66
0.94
0.88
—
in Somogyi units
or 100 ml. fluid
6
pH7.0
Phosphate
3,750
1,690
1,240
735
890
95
12,240
—
1,340
1,040
1,660
2,099,000
■ —
Mice
1
pH7.6
Veronal
3,360
1,590
1,210
710
840
91
12,500
—
1,310
900
1,620
,514,000
—
Ratio
0.90
0.94
0.98
0.97
0.94
0.96
1.02
—
0.98
0.87
0.98
0.72
—
° According to McGeachin et al. (44)·
b Determined according to the method of Van Loon et al. (46).
c Average of determinations in 15 individual animals, ranging from 91,000 to 1,340,000
units (45).
cerebrospinal fluid, and in the chicken egg (43). Many of the older
amylase determinations have been carried out in phosphate buffer, and
may include, therefore, phosphorylase activity. Newer measurements
(44) in Veronal buffer are more specific for amylase and yield results
shown in Table II.