Functional role of N-linked glycosylation in human hepatic lipase: asparagine-56 is important for both enzyme activity and secretion.

Angiotensin-converting enzyme 2 (ACE2) is expressed in the kidney and may be renoprotective. We determined whether urinary ACE2 enzyme activity and protein levels (ELISA), as well as angiotensinogen and ACE, are elevated during clamped euglycemia (4–6 mmol·L–1) in patients with uncomplicated type 1 diabetes (T1D, n = 58) compared with normoglycemic controls (n = 21). We also measured the effect of clamped hyperglycemia (9–11 mmol·L–1) on each urinary factor in T1D patients. Urinary ACE2 activity and protein levels were higher during clamped euglycemia in T1D compared with the controls (p < 0.0001). In contrast, urinary angiotensinogen levels (p = 0.27) and ACE excretion (p = 0.68) did not differ. In response to clamped hyperglycemia in T1D, urinary ACE2 protein decreased (p < 0.0001), whereas urinary ACE2 activity as well as angiotensinogen and ACE levels remained unchanged. Urinary ACE2 activity and protein expression are increased in T1D patients prior to the onset of clinical complications. Further work is required to determine the functional role of urinary ACE2 in early T1D.

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Functional role of a non-active site residue Trp23 on the enzyme activity of Escherichia coli thioesterase I/protease I/lysophospholipase L1

Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics ◽

10.1016/j.bbapap.2009.06.008 ◽

2009 ◽

Vol 1794 (10) ◽

pp. 1467-1473 ◽

Cited By ~ 11

Author(s):

Li-Chiun Lee ◽

Yi-Li Chou ◽

Hong-Hwa Chen ◽

Ya-Lin Lee ◽

Jei-Fu Shaw

Keyword(s):

Escherichia Coli ◽

Enzyme Activity ◽

Active Site ◽

Functional Role ◽

Active Site Residue

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Inhibition of calmodulin-dependent myosin light-chain kinase by growth-hormone-releasing factor and vasoactive intestinal peptide

Biochemical Journal ◽

10.1042/bj3000901 ◽

1994 ◽

Vol 300 (3) ◽

pp. 901-905 ◽

Cited By ~ 4

Author(s):

H Shiraga ◽

D Stallwood ◽

M Ebadi ◽

R Pfeiffer ◽

D Landers ◽

...

Keyword(s):

Growth Hormone ◽

Enzyme Activity ◽

Vasoactive Intestinal Peptide ◽

Light Chain ◽

Myosin Light Chain Kinase ◽

Functional Role ◽

Myosin Light Chain ◽

Growth Hormone Releasing Factor ◽

High Affinity

In view of the ability of calmodulin to bind vasoactive intestinal peptide (VIP) and growth-hormone-releasing factor (GRF) with high affinity [Stallwood, Brugger, Baggenstoss, Stemmer, Shiraga, Landers and Paul (1992) J. Biol. Chem. 267, 19617-19621], the effects of these neuropeptides on a model calmodulin-dependent enzyme, myosin light-chain kinase (MLCK), were studied. Both peptides were potent inhibitors of MLCK activity. The inhibition of enzyme activity by VIP and GRF was progressively overcome with increasing calmodulin concentrations, with no inhibition observed at a saturating calmodulin concentration. Nanomolar concentrations of MLCK blocked the formation of calmodulin-[125I-Tyr10]VIP complexes. These data provide support for a functional role of VIP and GRF binding by calmodulin.

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